octave: libcruft/arpack/src/slaqrb.f annotate

annotate libcruft/arpack/src/slaqrb.f @ 12274:9f5d2ef078e8 release-3-4-x

import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1

author	John W. Eaton <jwe@octave.org>
date	Fri, 28 Jan 2011 14:04:33 -0500
parents
children

rev	line source
12274 9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	1 c-----------------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	2 c\BeginDoc
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	3 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	4 c\Name: slaqrb
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	5 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	6 c\Description:
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	7 c Compute the eigenvalues and the Schur decomposition of an upper
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	8 c Hessenberg submatrix in rows and columns ILO to IHI. Only the
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	9 c last component of the Schur vectors are computed.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	10 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	11 c This is mostly a modification of the LAPACK routine slahqr.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	12 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	13 c\Usage:
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	14 c call slaqrb
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	15 c ( WANTT, N, ILO, IHI, H, LDH, WR, WI, Z, INFO )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	16 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	17 c\Arguments
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	18 c WANTT Logical variable. (INPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	19 c = .TRUE. : the full Schur form T is required;
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	20 c = .FALSE.: only eigenvalues are required.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	21 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	22 c N Integer. (INPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	23 c The order of the matrix H. N >= 0.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	24 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	25 c ILO Integer. (INPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	26 c IHI Integer. (INPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	27 c It is assumed that H is already upper quasi-triangular in
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	28 c rows and columns IHI+1:N, and that H(ILO,ILO-1) = 0 (unless
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	29 c ILO = 1). SLAQRB works primarily with the Hessenberg
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	30 c submatrix in rows and columns ILO to IHI, but applies
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	31 c transformations to all of H if WANTT is .TRUE..
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	32 c 1 <= ILO <= max(1,IHI); IHI <= N.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	33 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	34 c H Real array, dimension (LDH,N). (INPUT/OUTPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	35 c On entry, the upper Hessenberg matrix H.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	36 c On exit, if WANTT is .TRUE., H is upper quasi-triangular in
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	37 c rows and columns ILO:IHI, with any 2-by-2 diagonal blocks in
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	38 c standard form. If WANTT is .FALSE., the contents of H are
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	39 c unspecified on exit.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	40 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	41 c LDH Integer. (INPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	42 c The leading dimension of the array H. LDH >= max(1,N).
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	43 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	44 c WR Real array, dimension (N). (OUTPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	45 c WI Real array, dimension (N). (OUTPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	46 c The real and imaginary parts, respectively, of the computed
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	47 c eigenvalues ILO to IHI are stored in the corresponding
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	48 c elements of WR and WI. If two eigenvalues are computed as a
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	49 c complex conjugate pair, they are stored in consecutive
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	50 c elements of WR and WI, say the i-th and (i+1)th, with
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	51 c WI(i) > 0 and WI(i+1) < 0. If WANTT is .TRUE., the
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	52 c eigenvalues are stored in the same order as on the diagonal
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	53 c of the Schur form returned in H, with WR(i) = H(i,i), and, if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	54 c H(i:i+1,i:i+1) is a 2-by-2 diagonal block,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	55 c WI(i) = sqrt(H(i+1,i)*H(i,i+1)) and WI(i+1) = -WI(i).
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	56 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	57 c Z Real array, dimension (N). (OUTPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	58 c On exit Z contains the last components of the Schur vectors.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	59 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	60 c INFO Integer. (OUPUT)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	61 c = 0: successful exit
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	62 c > 0: SLAQRB failed to compute all the eigenvalues ILO to IHI
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	63 c in a total of 30*(IHI-ILO+1) iterations; if INFO = i,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	64 c elements i+1:ihi of WR and WI contain those eigenvalues
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	65 c which have been successfully computed.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	66 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	67 c\Remarks
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	68 c 1. None.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	69 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	70 c-----------------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	71 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	72 c\BeginLib
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	73 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	74 c\Local variables:
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	75 c xxxxxx real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	76 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	77 c\Routines called:
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	78 c slabad LAPACK routine that computes machine constants.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	79 c slamch LAPACK routine that determines machine constants.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	80 c slanhs LAPACK routine that computes various norms of a matrix.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	81 c slanv2 LAPACK routine that computes the Schur factorization of
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	82 c 2 by 2 nonsymmetric matrix in standard form.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	83 c slarfg LAPACK Householder reflection construction routine.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	84 c scopy Level 1 BLAS that copies one vector to another.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	85 c srot Level 1 BLAS that applies a rotation to a 2 by 2 matrix.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	86
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	87 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	88 c\Author
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	89 c Danny Sorensen Phuong Vu
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	90 c Richard Lehoucq CRPC / Rice University
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	91 c Dept. of Computational & Houston, Texas
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	92 c Applied Mathematics
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	93 c Rice University
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	94 c Houston, Texas
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	95 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	96 c\Revision history:
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	97 c xx/xx/92: Version ' 2.4'
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	98 c Modified from the LAPACK routine slahqr so that only the
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	99 c last component of the Schur vectors are computed.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	100 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	101 c\SCCS Information: @(#)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	102 c FILE: laqrb.F SID: 2.2 DATE OF SID: 8/27/96 RELEASE: 2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	103 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	104 c\Remarks
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	105 c 1. None
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	106 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	107 c\EndLib
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	108 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	109 c-----------------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	110 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	111 subroutine slaqrb ( wantt, n, ilo, ihi, h, ldh, wr, wi,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	112 & z, info )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	113 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	114 c %------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	115 c \| Scalar Arguments \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	116 c %------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	117 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	118 logical wantt
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	119 integer ihi, ilo, info, ldh, n
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	120 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	121 c %-----------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	122 c \| Array Arguments \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	123 c %-----------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	124 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	125 Real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	126 & h( ldh, * ), wi( * ), wr( * ), z( * )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	127 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	128 c %------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	129 c \| Parameters \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	130 c %------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	131 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	132 Real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	133 & zero, one, dat1, dat2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	134 parameter (zero = 0.0E+0, one = 1.0E+0, dat1 = 7.5E-1,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	135 & dat2 = -4.375E-1)
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	136 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	137 c %------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	138 c \| Local Scalars & Arrays \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	139 c %------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	140 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	141 integer i, i1, i2, itn, its, j, k, l, m, nh, nr
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	142 Real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	143 & cs, h00, h10, h11, h12, h21, h22, h33, h33s,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	144 & h43h34, h44, h44s, ovfl, s, smlnum, sn, sum,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	145 & t1, t2, t3, tst1, ulp, unfl, v1, v2, v3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	146 Real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	147 & v( 3 ), work( 1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	148 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	149 c %--------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	150 c \| External Functions \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	151 c %--------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	152 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	153 Real
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	154 & slamch, slanhs
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	155 external slamch, slanhs
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	156 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	157 c %----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	158 c \| External Subroutines \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	159 c %----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	160 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	161 external scopy, slabad, slanv2, slarfg, srot
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	162 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	163 c %-----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	164 c \| Executable Statements \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	165 c %-----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	166 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	167 info = 0
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	168 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	169 c %--------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	170 c \| Quick return if possible \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	171 c %--------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	172 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	173 if( n.eq.0 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	174 & return
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	175 if( ilo.eq.ihi ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	176 wr( ilo ) = h( ilo, ilo )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	177 wi( ilo ) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	178 return
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	179 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	180 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	181 c %---------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	182 c \| Initialize the vector of last components of \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	183 c \| the Schur vectors for accumulation. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	184 c %---------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	185 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	186 do 5 j = 1, n-1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	187 z(j) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	188 5 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	189 z(n) = one
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	190 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	191 nh = ihi - ilo + 1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	192 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	193 c %-------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	194 c \| Set machine-dependent constants for the stopping criterion. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	195 c \| If norm(H) <= sqrt(OVFL), overflow should not occur. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	196 c %-------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	197 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	198 unfl = slamch( 'safe minimum' )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	199 ovfl = one / unfl
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	200 call slabad( unfl, ovfl )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	201 ulp = slamch( 'precision' )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	202 smlnum = unfl*( nh / ulp )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	203 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	204 c %---------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	205 c \| I1 and I2 are the indices of the first row and last column \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	206 c \| of H to which transformations must be applied. If eigenvalues \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	207 c \| only are computed, I1 and I2 are set inside the main loop. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	208 c \| Zero out H(J+2,J) = ZERO for J=1:N if WANTT = .TRUE. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	209 c \| else H(J+2,J) for J=ILO:IHI-ILO-1 if WANTT = .FALSE. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	210 c %---------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	211 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	212 if( wantt ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	213 i1 = 1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	214 i2 = n
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	215 do 8 i=1,i2-2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	216 h(i1+i+1,i) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	217 8 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	218 else
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	219 do 9 i=1, ihi-ilo-1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	220 h(ilo+i+1,ilo+i-1) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	221 9 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	222 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	223 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	224 c %---------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	225 c \| ITN is the total number of QR iterations allowed. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	226 c %---------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	227 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	228 itn = 30*nh
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	229 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	230 c ------------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	231 c The main loop begins here. I is the loop index and decreases from
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	232 c IHI to ILO in steps of 1 or 2. Each iteration of the loop works
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	233 c with the active submatrix in rows and columns L to I.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	234 c Eigenvalues I+1 to IHI have already converged. Either L = ILO or
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	235 c H(L,L-1) is negligible so that the matrix splits.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	236 c ------------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	237 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	238 i = ihi
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	239 10 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	240 l = ilo
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	241 if( i.lt.ilo )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	242 & go to 150
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	243
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	244 c %--------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	245 c \| Perform QR iterations on rows and columns ILO to I until a \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	246 c \| submatrix of order 1 or 2 splits off at the bottom because a \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	247 c \| subdiagonal element has become negligible. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	248 c %--------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	249
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	250 do 130 its = 0, itn
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	251 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	252 c %----------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	253 c \| Look for a single small subdiagonal element. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	254 c %----------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	255 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	256 do 20 k = i, l + 1, -1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	257 tst1 = abs( h( k-1, k-1 ) ) + abs( h( k, k ) )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	258 if( tst1.eq.zero )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	259 & tst1 = slanhs( '1', i-l+1, h( l, l ), ldh, work )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	260 if( abs( h( k, k-1 ) ).le.max( ulp*tst1, smlnum ) )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	261 & go to 30
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	262 20 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	263 30 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	264 l = k
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	265 if( l.gt.ilo ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	266 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	267 c %------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	268 c \| H(L,L-1) is negligible \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	269 c %------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	270 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	271 h( l, l-1 ) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	272 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	273 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	274 c %-------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	275 c \| Exit from loop if a submatrix of order 1 or 2 has split off \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	276 c %-------------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	277 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	278 if( l.ge.i-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	279 & go to 140
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	280 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	281 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	282 c \| Now the active submatrix is in rows and columns L to I. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	283 c \| If eigenvalues only are being computed, only the active \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	284 c \| submatrix need be transformed. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	285 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	286 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	287 if( .not.wantt ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	288 i1 = l
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	289 i2 = i
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	290 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	291 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	292 if( its.eq.10 .or. its.eq.20 ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	293 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	294 c %-------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	295 c \| Exceptional shift \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	296 c %-------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	297 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	298 s = abs( h( i, i-1 ) ) + abs( h( i-1, i-2 ) )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	299 h44 = dat1*s
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	300 h33 = h44
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	301 h43h34 = dat2ss
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	302 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	303 else
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	304 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	305 c %-----------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	306 c \| Prepare to use Wilkinson's double shift \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	307 c %-----------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	308 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	309 h44 = h( i, i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	310 h33 = h( i-1, i-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	311 h43h34 = h( i, i-1 )*h( i-1, i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	312 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	313 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	314 c %-----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	315 c \| Look for two consecutive small subdiagonal elements \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	316 c %-----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	317 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	318 do 40 m = i - 2, l, -1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	319 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	320 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	321 c \| Determine the effect of starting the double-shift QR \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	322 c \| iteration at row M, and see if this would make H(M,M-1) \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	323 c \| negligible. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	324 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	325 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	326 h11 = h( m, m )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	327 h22 = h( m+1, m+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	328 h21 = h( m+1, m )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	329 h12 = h( m, m+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	330 h44s = h44 - h11
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	331 h33s = h33 - h11
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	332 v1 = ( h33s*h44s-h43h34 ) / h21 + h12
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	333 v2 = h22 - h11 - h33s - h44s
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	334 v3 = h( m+2, m+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	335 s = abs( v1 ) + abs( v2 ) + abs( v3 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	336 v1 = v1 / s
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	337 v2 = v2 / s
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	338 v3 = v3 / s
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	339 v( 1 ) = v1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	340 v( 2 ) = v2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	341 v( 3 ) = v3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	342 if( m.eq.l )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	343 & go to 50
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	344 h00 = h( m-1, m-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	345 h10 = h( m, m-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	346 tst1 = abs( v1 )*( abs( h00 )+abs( h11 )+abs( h22 ) )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	347 if( abs( h10 )( abs( v2 )+abs( v3 ) ).le.ulptst1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	348 & go to 50
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	349 40 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	350 50 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	351 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	352 c %----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	353 c \| Double-shift QR step \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	354 c %----------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	355 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	356 do 120 k = m, i - 1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	357 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	358 c ------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	359 c The first iteration of this loop determines a reflection G
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	360 c from the vector V and applies it from left and right to H,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	361 c thus creating a nonzero bulge below the subdiagonal.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	362 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	363 c Each subsequent iteration determines a reflection G to
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	364 c restore the Hessenberg form in the (K-1)th column, and thus
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	365 c chases the bulge one step toward the bottom of the active
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	366 c submatrix. NR is the order of G.
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	367 c ------------------------------------------------------------
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	368 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	369 nr = min( 3, i-k+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	370 if( k.gt.m )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	371 & call scopy( nr, h( k, k-1 ), 1, v, 1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	372 call slarfg( nr, v( 1 ), v( 2 ), 1, t1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	373 if( k.gt.m ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	374 h( k, k-1 ) = v( 1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	375 h( k+1, k-1 ) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	376 if( k.lt.i-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	377 & h( k+2, k-1 ) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	378 else if( m.gt.l ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	379 h( k, k-1 ) = -h( k, k-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	380 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	381 v2 = v( 2 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	382 t2 = t1*v2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	383 if( nr.eq.3 ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	384 v3 = v( 3 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	385 t3 = t1*v3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	386 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	387 c %------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	388 c \| Apply G from the left to transform the rows of \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	389 c \| the matrix in columns K to I2. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	390 c %------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	391 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	392 do 60 j = k, i2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	393 sum = h( k, j ) + v2h( k+1, j ) + v3h( k+2, j )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	394 h( k, j ) = h( k, j ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	395 h( k+1, j ) = h( k+1, j ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	396 h( k+2, j ) = h( k+2, j ) - sum*t3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	397 60 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	398 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	399 c %----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	400 c \| Apply G from the right to transform the columns of \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	401 c \| the matrix in rows I1 to min(K+3,I). \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	402 c %----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	403 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	404 do 70 j = i1, min( k+3, i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	405 sum = h( j, k ) + v2h( j, k+1 ) + v3h( j, k+2 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	406 h( j, k ) = h( j, k ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	407 h( j, k+1 ) = h( j, k+1 ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	408 h( j, k+2 ) = h( j, k+2 ) - sum*t3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	409 70 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	410 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	411 c %----------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	412 c \| Accumulate transformations for Z \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	413 c %----------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	414 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	415 sum = z( k ) + v2z( k+1 ) + v3z( k+2 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	416 z( k ) = z( k ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	417 z( k+1 ) = z( k+1 ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	418 z( k+2 ) = z( k+2 ) - sum*t3
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	419
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	420 else if( nr.eq.2 ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	421 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	422 c %------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	423 c \| Apply G from the left to transform the rows of \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	424 c \| the matrix in columns K to I2. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	425 c %------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	426 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	427 do 90 j = k, i2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	428 sum = h( k, j ) + v2*h( k+1, j )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	429 h( k, j ) = h( k, j ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	430 h( k+1, j ) = h( k+1, j ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	431 90 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	432 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	433 c %----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	434 c \| Apply G from the right to transform the columns of \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	435 c \| the matrix in rows I1 to min(K+3,I). \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	436 c %----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	437 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	438 do 100 j = i1, i
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	439 sum = h( j, k ) + v2*h( j, k+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	440 h( j, k ) = h( j, k ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	441 h( j, k+1 ) = h( j, k+1 ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	442 100 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	443 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	444 c %----------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	445 c \| Accumulate transformations for Z \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	446 c %----------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	447 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	448 sum = z( k ) + v2*z( k+1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	449 z( k ) = z( k ) - sum*t1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	450 z( k+1 ) = z( k+1 ) - sum*t2
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	451 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	452 120 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	453
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	454 130 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	455 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	456 c %-------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	457 c \| Failure to converge in remaining number of iterations \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	458 c %-------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	459 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	460 info = i
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	461 return
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	462
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	463 140 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	464
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	465 if( l.eq.i ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	466 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	467 c %------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	468 c \| H(I,I-1) is negligible: one eigenvalue has converged \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	469 c %------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	470 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	471 wr( i ) = h( i, i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	472 wi( i ) = zero
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	473
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	474 else if( l.eq.i-1 ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	475 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	476 c %--------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	477 c \| H(I-1,I-2) is negligible; \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	478 c \| a pair of eigenvalues have converged. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	479 c \| \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	480 c \| Transform the 2-by-2 submatrix to standard Schur form, \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	481 c \| and compute and store the eigenvalues. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	482 c %--------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	483 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	484 call slanv2( h( i-1, i-1 ), h( i-1, i ), h( i, i-1 ),
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	485 & h( i, i ), wr( i-1 ), wi( i-1 ), wr( i ), wi( i ),
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	486 & cs, sn )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	487
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	488 if( wantt ) then
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	489 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	490 c %-----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	491 c \| Apply the transformation to the rest of H and to Z, \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	492 c \| as required. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	493 c %-----------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	494 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	495 if( i2.gt.i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	496 & call srot( i2-i, h( i-1, i+1 ), ldh, h( i, i+1 ), ldh,
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	497 & cs, sn )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	498 call srot( i-i1-1, h( i1, i-1 ), 1, h( i1, i ), 1, cs, sn )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	499 sum = csz( i-1 ) + snz( i )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	500 z( i ) = csz( i ) - snz( i-1 )
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	501 z( i-1 ) = sum
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	502 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	503 end if
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	504 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	505 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	506 c \| Decrement number of remaining iterations, and return to \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	507 c \| start of the main loop with new value of I. \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	508 c %---------------------------------------------------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	509 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	510 itn = itn - its
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	511 i = l - 1
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	512 go to 10
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	513
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	514 150 continue
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	515 return
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	516 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	517 c %---------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	518 c \| End of slaqrb \|
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	519 c %---------------%
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	520 c
9f5d2ef078e8 import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1 John W. Eaton <jwe@octave.org> parents: diff changeset	521 end

Mercurial > octave

annotate libcruft/arpack/src/slaqrb.f @ 12274:9f5d2ef078e8 release-3-4-x