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author | jason <jason@8a072113-8704-0410-8d35-dd094bca7971> | 2008-10-28 01:38:50 +0000 |
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committer | jason <jason@8a072113-8704-0410-8d35-dd094bca7971> | 2008-10-28 01:38:50 +0000 |
commit | baba851215b44ac3b60b9248eb02bcce7eb76247 (patch) | |
tree | 8c0f5c006875532a30d4409f5e94b0f310ff00a7 /BLAS/SRC/dscal.f | |
download | lapack-baba851215b44ac3b60b9248eb02bcce7eb76247.tar.gz lapack-baba851215b44ac3b60b9248eb02bcce7eb76247.tar.bz2 lapack-baba851215b44ac3b60b9248eb02bcce7eb76247.zip |
Move LAPACK trunk into position.
Diffstat (limited to 'BLAS/SRC/dscal.f')
-rw-r--r-- | BLAS/SRC/dscal.f | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/BLAS/SRC/dscal.f b/BLAS/SRC/dscal.f new file mode 100644 index 00000000..0b423cf2 --- /dev/null +++ b/BLAS/SRC/dscal.f @@ -0,0 +1,57 @@ + SUBROUTINE DSCAL(N,DA,DX,INCX) +* .. Scalar Arguments .. + DOUBLE PRECISION DA + INTEGER INCX,N +* .. +* .. Array Arguments .. + DOUBLE PRECISION DX(*) +* .. +* +* Purpose +* ======= +** +* scales a vector by a constant. +* uses unrolled loops for increment equal to one. +* 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 + DX(I) = DA*DX(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 + 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 |