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84 lines
1.6 KiB
C
84 lines
1.6 KiB
C
#include "clapack.h"
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/* Subroutine */ int dscal_(integer *n, doublereal *da, doublereal *dx,
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integer *incx)
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{
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/* System generated locals */
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integer i__1, i__2;
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/* Local variables */
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integer i__, m, mp1, nincx;
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* * */
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/* scales a vector by a constant. */
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/* uses unrolled loops for increment equal to one. */
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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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/* .. Local Scalars .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* Parameter adjustments */
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--dx;
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/* Function Body */
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if (*n <= 0 || *incx <= 0) {
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return 0;
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}
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if (*incx == 1) {
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goto L20;
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}
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/* code for increment not equal to 1 */
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nincx = *n * *incx;
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i__1 = nincx;
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i__2 = *incx;
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for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
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dx[i__] = *da * dx[i__];
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/* L10: */
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}
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return 0;
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/* code for increment equal to 1 */
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/* clean-up loop */
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L20:
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m = *n % 5;
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if (m == 0) {
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goto L40;
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}
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i__2 = m;
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for (i__ = 1; i__ <= i__2; ++i__) {
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dx[i__] = *da * dx[i__];
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/* L30: */
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}
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if (*n < 5) {
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return 0;
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}
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L40:
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mp1 = m + 1;
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i__2 = *n;
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for (i__ = mp1; i__ <= i__2; i__ += 5) {
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dx[i__] = *da * dx[i__];
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dx[i__ + 1] = *da * dx[i__ + 1];
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dx[i__ + 2] = *da * dx[i__ + 2];
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dx[i__ + 3] = *da * dx[i__ + 3];
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dx[i__ + 4] = *da * dx[i__ + 4];
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/* L50: */
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}
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return 0;
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} /* dscal_ */
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