Mercurial > octave-nkf
diff libcruft/lapack/sorghr.f @ 7789:82be108cc558
First attempt at single precision tyeps
* * *
corrections to qrupdate single precision routines
* * *
prefer demotion to single over promotion to double
* * *
Add single precision support to log2 function
* * *
Trivial PROJECT file update
* * *
Cache optimized hermitian/transpose methods
* * *
Add tests for tranpose/hermitian and ChangeLog entry for new transpose code
author | David Bateman <dbateman@free.fr> |
---|---|
date | Sun, 27 Apr 2008 22:34:17 +0200 |
parents | |
children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libcruft/lapack/sorghr.f Sun Apr 27 22:34:17 2008 +0200 @@ -0,0 +1,164 @@ + SUBROUTINE SORGHR( N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO ) +* +* -- LAPACK routine (version 3.1) -- +* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. +* November 2006 +* +* .. Scalar Arguments .. + INTEGER IHI, ILO, INFO, LDA, LWORK, N +* .. +* .. Array Arguments .. + REAL A( LDA, * ), TAU( * ), WORK( * ) +* .. +* +* Purpose +* ======= +* +* SORGHR generates a real orthogonal matrix Q which is defined as the +* product of IHI-ILO elementary reflectors of order N, as returned by +* SGEHRD: +* +* Q = H(ilo) H(ilo+1) . . . H(ihi-1). +* +* Arguments +* ========= +* +* N (input) INTEGER +* The order of the matrix Q. N >= 0. +* +* ILO (input) INTEGER +* IHI (input) INTEGER +* ILO and IHI must have the same values as in the previous call +* of SGEHRD. Q is equal to the unit matrix except in the +* submatrix Q(ilo+1:ihi,ilo+1:ihi). +* 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0. +* +* A (input/output) REAL array, dimension (LDA,N) +* On entry, the vectors which define the elementary reflectors, +* as returned by SGEHRD. +* On exit, the N-by-N orthogonal matrix Q. +* +* LDA (input) INTEGER +* The leading dimension of the array A. LDA >= max(1,N). +* +* TAU (input) REAL array, dimension (N-1) +* TAU(i) must contain the scalar factor of the elementary +* reflector H(i), as returned by SGEHRD. +* +* WORK (workspace/output) REAL array, dimension (MAX(1,LWORK)) +* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. +* +* LWORK (input) INTEGER +* The dimension of the array WORK. LWORK >= IHI-ILO. +* For optimum performance LWORK >= (IHI-ILO)*NB, where NB is +* the optimal blocksize. +* +* If LWORK = -1, then a workspace query is assumed; the routine +* only calculates the optimal size of the WORK array, returns +* this value as the first entry of the WORK array, and no error +* message related to LWORK is issued by XERBLA. +* +* INFO (output) INTEGER +* = 0: successful exit +* < 0: if INFO = -i, the i-th argument had an illegal value +* +* ===================================================================== +* +* .. Parameters .. + REAL ZERO, ONE + PARAMETER ( ZERO = 0.0E+0, ONE = 1.0E+0 ) +* .. +* .. Local Scalars .. + LOGICAL LQUERY + INTEGER I, IINFO, J, LWKOPT, NB, NH +* .. +* .. External Subroutines .. + EXTERNAL SORGQR, XERBLA +* .. +* .. External Functions .. + INTEGER ILAENV + EXTERNAL ILAENV +* .. +* .. Intrinsic Functions .. + INTRINSIC MAX, MIN +* .. +* .. Executable Statements .. +* +* Test the input arguments +* + INFO = 0 + NH = IHI - ILO + LQUERY = ( LWORK.EQ.-1 ) + IF( N.LT.0 ) THEN + INFO = -1 + ELSE IF( ILO.LT.1 .OR. ILO.GT.MAX( 1, N ) ) THEN + INFO = -2 + ELSE IF( IHI.LT.MIN( ILO, N ) .OR. IHI.GT.N ) THEN + INFO = -3 + ELSE IF( LDA.LT.MAX( 1, N ) ) THEN + INFO = -5 + ELSE IF( LWORK.LT.MAX( 1, NH ) .AND. .NOT.LQUERY ) THEN + INFO = -8 + END IF +* + IF( INFO.EQ.0 ) THEN + NB = ILAENV( 1, 'SORGQR', ' ', NH, NH, NH, -1 ) + LWKOPT = MAX( 1, NH )*NB + WORK( 1 ) = LWKOPT + END IF +* + IF( INFO.NE.0 ) THEN + CALL XERBLA( 'SORGHR', -INFO ) + RETURN + ELSE IF( LQUERY ) THEN + RETURN + END IF +* +* Quick return if possible +* + IF( N.EQ.0 ) THEN + WORK( 1 ) = 1 + RETURN + END IF +* +* Shift the vectors which define the elementary reflectors one +* column to the right, and set the first ilo and the last n-ihi +* rows and columns to those of the unit matrix +* + DO 40 J = IHI, ILO + 1, -1 + DO 10 I = 1, J - 1 + A( I, J ) = ZERO + 10 CONTINUE + DO 20 I = J + 1, IHI + A( I, J ) = A( I, J-1 ) + 20 CONTINUE + DO 30 I = IHI + 1, N + A( I, J ) = ZERO + 30 CONTINUE + 40 CONTINUE + DO 60 J = 1, ILO + DO 50 I = 1, N + A( I, J ) = ZERO + 50 CONTINUE + A( J, J ) = ONE + 60 CONTINUE + DO 80 J = IHI + 1, N + DO 70 I = 1, N + A( I, J ) = ZERO + 70 CONTINUE + A( J, J ) = ONE + 80 CONTINUE +* + IF( NH.GT.0 ) THEN +* +* Generate Q(ilo+1:ihi,ilo+1:ihi) +* + CALL SORGQR( NH, NH, NH, A( ILO+1, ILO+1 ), LDA, TAU( ILO ), + $ WORK, LWORK, IINFO ) + END IF + WORK( 1 ) = LWKOPT + RETURN +* +* End of SORGHR +* + END