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Implement sparse * diagonal and diagonal * sparse operations, double-prec only. Date: Sun, 8 Mar 2009 16:28:18 -0400 These preserve sparsity, so eye(5) * sprand (5, 5, .2) is *sparse* and not dense. This may affect people who use multiplication by eye() rather than full(). The liboctave routines do *not* check if arguments are scalars in disguise. There is a type problem with checking at that level. I suspect we want diag * "sparse scalar" to stay diagonal, but we have to return a sparse matrix at the liboctave. Rather than worrying about that in liboctave, we cope with it when binding to Octave and return the correct higher-level type. The implementation is in Sparse-diag-op-defs.h rather than Sparse-op-defs.h to limit recompilation. And the implementations are templates rather than macros to produce better compiler errors and debugging information.
author Jason Riedy <jason@acm.org>
date Mon, 09 Mar 2009 17:49:13 -0400
parents 8b0cb8f79fdc
children
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      SUBROUTINE XZLOG(AR, AI, BR, BI, IERR)
C***BEGIN PROLOGUE  XZLOG
C***REFER TO  ZBESH,ZBESI,ZBESJ,ZBESK,ZBESY,ZAIRY,ZBIRY
C
C     DOUBLE PRECISION COMPLEX LOGARITHM B=CLOG(A)
C     IERR=0,NORMAL RETURN      IERR=1, Z=CMPLX(0.0,0.0)
C***ROUTINES CALLED  XZABS
C***END PROLOGUE  XZLOG
      DOUBLE PRECISION AR, AI, BR, BI, ZM, DTHETA, DPI, DHPI
      DOUBLE PRECISION XZABS
      DATA DPI , DHPI  / 3.141592653589793238462643383D+0,
     1                   1.570796326794896619231321696D+0/
C
      IERR=0
      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.EQ.0.0D+0) GO TO 60
      BI = DHPI
      BR = DLOG(DABS(AI))
      IF (AI.LT.0.0D+0) BI = -BI
      RETURN
   20 IF (AR.GT.0.0D+0) GO TO 30
      BR = DLOG(DABS(AR))
      BI = DPI
      RETURN
   30 BR = DLOG(AR)
      BI = 0.0D+0
      RETURN
   40 IF (AR.LT.0.0D+0) DTHETA = DTHETA + DPI
   50 ZM = XZABS(AR,AI)
      BR = DLOG(ZM)
      BI = DTHETA
      RETURN
   60 CONTINUE
      IERR=1
      RETURN
      END