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45 lines
1.0 KiB
C
45 lines
1.0 KiB
C
#include "blas.h"
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int dscal_(int *n, double *sa, double *sx, int *incx)
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{
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long int i, m, nincx, nn, iincx;
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double ssa;
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/* scales a vector by a constant.
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uses unrolled loops for increment equal to 1.
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jack dongarra, linpack, 3/11/78.
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modified 3/93 to return if incx .le. 0.
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modified 12/3/93, array(1) declarations changed to array(*) */
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/* Dereference inputs */
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nn = *n;
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iincx = *incx;
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ssa = *sa;
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if (nn > 0 && iincx > 0)
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{
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if (iincx == 1) /* code for increment equal to 1 */
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{
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m = nn-4;
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for (i = 0; i < m; i += 5)
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{
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sx[i] = ssa * sx[i];
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sx[i+1] = ssa * sx[i+1];
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sx[i+2] = ssa * sx[i+2];
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sx[i+3] = ssa * sx[i+3];
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sx[i+4] = ssa * sx[i+4];
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}
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for ( ; i < nn; ++i) /* clean-up loop */
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sx[i] = ssa * sx[i];
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}
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else /* code for increment not equal to 1 */
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{
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nincx = nn * iincx;
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for (i = 0; i < nincx; i += iincx)
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sx[i] = ssa * sx[i];
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}
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}
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return 0;
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} /* dscal_ */
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