76 lines
1.4 KiB
C
76 lines
1.4 KiB
C
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/* -- translated by f2c (version 19940927).
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You must link the resulting object file with the libraries:
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-lf2c -lm (in that order)
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*/
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#include "f2c.h"
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/* Subroutine */ int drot_(integer *n, doublereal *dx, integer *incx,
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doublereal *dy, integer *incy, doublereal *c, doublereal *s)
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{
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/* System generated locals */
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integer i__1;
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/* Local variables */
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static integer i;
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static doublereal dtemp;
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static integer ix, iy;
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/* applies a plane rotation.
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jack dongarra, linpack, 3/11/78.
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modified 12/3/93, array(1) declarations changed to array(*)
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Parameter adjustments
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Function Body */
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#define DY(I) dy[(I)-1]
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#define DX(I) dx[(I)-1]
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if (*n <= 0) {
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return 0;
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}
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if (*incx == 1 && *incy == 1) {
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goto L20;
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}
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/* code for unequal increments or equal increments not equal
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to 1 */
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ix = 1;
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iy = 1;
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if (*incx < 0) {
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ix = (-(*n) + 1) * *incx + 1;
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}
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if (*incy < 0) {
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iy = (-(*n) + 1) * *incy + 1;
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}
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i__1 = *n;
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for (i = 1; i <= *n; ++i) {
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dtemp = *c * DX(ix) + *s * DY(iy);
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DY(iy) = *c * DY(iy) - *s * DX(ix);
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DX(ix) = dtemp;
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ix += *incx;
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iy += *incy;
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/* L10: */
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}
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return 0;
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/* code for both increments equal to 1 */
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L20:
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i__1 = *n;
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for (i = 1; i <= *n; ++i) {
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dtemp = *c * DX(i) + *s * DY(i);
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DY(i) = *c * DY(i) - *s * DX(i);
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DX(i) = dtemp;
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/* L30: */
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}
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return 0;
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} /* drot_ */
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