Mercurial > octave
view libcruft/blas/dscal.f @ 2329:30c606bec7a8
[project @ 1996-07-19 01:29:05 by jwe]
Initial revision
author | jwe |
---|---|
date | Fri, 19 Jul 1996 01:29:55 +0000 |
parents | |
children | bac14003d9bb |
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SUBROUTINE DSCAL(N,DA,DX,INCX) C C SCALES A VECTOR BY A CONSTANT. C USES UNROLLED LOOPS FOR INCREMENT EQUAL TO ONE. C JACK DONGARRA, LINPACK, 3/11/78. C DOUBLE PRECISION DA,DX(1) INTEGER I,INCX,M,MP1,N,NINCX C IF(N.LE.0)RETURN IF(INCX.EQ.1)GO TO 20 C C CODE FOR INCREMENT NOT EQUAL TO 1 C NINCX = N*INCX DO 10 I = 1,NINCX,INCX DX(I) = DA*DX(I) 10 CONTINUE RETURN C C CODE FOR INCREMENT EQUAL TO 1 C C C CLEAN-UP LOOP C 20 M = MOD(N,5) IF( M .EQ. 0 ) GO TO 40 DO 30 I = 1,M DX(I) = DA*DX(I) 30 CONTINUE IF( N .LT. 5 ) RETURN 40 MP1 = M + 1 DO 50 I = MP1,N,5 DX(I) = DA*DX(I) DX(I + 1) = DA*DX(I + 1) DX(I + 2) = DA*DX(I + 2) DX(I + 3) = DA*DX(I + 3) DX(I + 4) = DA*DX(I + 4) 50 CONTINUE RETURN END