Mercurial > octave
view liboctave/external/amos/xzsqrt.f @ 23434:f4d4d83f15c5
maint: rename cruft/ directory to external/
* liboctave/external: Renamed from liboctave/cruft.
*
* configure.ac: Rename XTRA_CRUFT_SH_LDFLAGS to XTRA_EXTERNAL_SH_LDFLAGS.
Rename CRUFT_DLL_DEFS to EXTERNAL_DLL_DEFS.
* install.txi: Update documentation to refer to liboctave/external.
* HACKING: Update explanation of directory tree.
* liboctave/module.mk: Update build system to include liboctave/external
* liboctave/numeric/module.mk: Update CPPFLAGS to find Faddeeva in external/
directory.
* lo-blas-proto.h, lo-lapack-proto.h: Update comments which referred to cruft
directory.
author | Rik <rik@octave.org> |
---|---|
date | Mon, 24 Apr 2017 21:03:38 -0700 |
parents | liboctave/cruft/amos/xzsqrt.f@648dabbb4c6b |
children |
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SUBROUTINE XZSQRT(AR, AI, BR, BI) C***BEGIN PROLOGUE XZSQRT C***REFER TO ZBESH,ZBESI,ZBESJ,ZBESK,ZBESY,ZAIRY,ZBIRY C C DOUBLE PRECISION COMPLEX SQUARE ROOT, B=CSQRT(A) C C***ROUTINES CALLED XZABS C***END PROLOGUE XZSQRT DOUBLE PRECISION AR, AI, BR, BI, ZM, DTHETA, DPI, DRT DOUBLE PRECISION XZABS DATA DRT , DPI / 7.071067811865475244008443621D-1, 1 3.141592653589793238462643383D+0/ ZM = XZABS(AR,AI) ZM = DSQRT(ZM) IF (AR.EQ.0.0D+0) GO TO 10 IF (AI.EQ.0.0D+0) GO TO 20 DTHETA = DATAN(AI/AR) IF (DTHETA.LE.0.0D+0) GO TO 40 IF (AR.LT.0.0D+0) DTHETA = DTHETA - DPI GO TO 50 10 IF (AI.GT.0.0D+0) GO TO 60 IF (AI.LT.0.0D+0) GO TO 70 BR = 0.0D+0 BI = 0.0D+0 RETURN 20 IF (AR.GT.0.0D+0) GO TO 30 BR = 0.0D+0 BI = DSQRT(DABS(AR)) RETURN 30 BR = DSQRT(AR) BI = 0.0D+0 RETURN 40 IF (AR.LT.0.0D+0) DTHETA = DTHETA + DPI 50 DTHETA = DTHETA*0.5D+0 BR = ZM*DCOS(DTHETA) BI = ZM*DSIN(DTHETA) RETURN 60 BR = ZM*DRT BI = ZM*DRT RETURN 70 BR = ZM*DRT BI = -ZM*DRT RETURN END