87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
/* drot.f -- translated by f2c (version 20061008).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "clapack.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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integer i__, ix, iy;
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doublereal dtemp;
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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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/* 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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/* .. Local Scalars .. */
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/* .. */
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/* Parameter adjustments */
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--dy;
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--dx;
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/* Function Body */
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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__ <= i__1; ++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__ <= i__1; ++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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