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view libcruft/blas/sscal.f @ 8924:3c3cbe8f18e0 ss-3-1-54
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author | John W. Eaton <jwe@octave.org> |
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date | Sat, 07 Mar 2009 13:28:03 -0500 |
parents | 82be108cc558 |
children |
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SUBROUTINE SSCAL(N,SA,SX,INCX) * .. Scalar Arguments .. REAL SA INTEGER INCX,N * .. * .. Array Arguments .. REAL SX(*) * .. * * Purpose * ======= * * scales a vector by a constant. * uses unrolled loops for increment equal to 1. * jack dongarra, linpack, 3/11/78. * modified 3/93 to return if incx .le. 0. * modified 12/3/93, array(1) declarations changed to array(*) * * * .. Local Scalars .. INTEGER I,M,MP1,NINCX * .. * .. Intrinsic Functions .. INTRINSIC MOD * .. IF (N.LE.0 .OR. INCX.LE.0) RETURN IF (INCX.EQ.1) GO TO 20 * * code for increment not equal to 1 * NINCX = N*INCX DO 10 I = 1,NINCX,INCX SX(I) = SA*SX(I) 10 CONTINUE RETURN * * code for increment equal to 1 * * * clean-up loop * 20 M = MOD(N,5) IF (M.EQ.0) GO TO 40 DO 30 I = 1,M SX(I) = SA*SX(I) 30 CONTINUE IF (N.LT.5) RETURN 40 MP1 = M + 1 DO 50 I = MP1,N,5 SX(I) = SA*SX(I) SX(I+1) = SA*SX(I+1) SX(I+2) = SA*SX(I+2) SX(I+3) = SA*SX(I+3) SX(I+4) = SA*SX(I+4) 50 CONTINUE RETURN END