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/* blas/drot.f -- translated by f2c (version 20050501).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "v3p_netlib.h"
/*< subroutine drot (n,dx,incx,dy,incy,c,s) >*/
/* Subroutine */ int drot_(integer *n, doublereal *dx, integer *incx,
doublereal *dy, integer *incy, doublereal *c__, doublereal *s)
{
/* System generated locals */
integer i__1;
/* Local variables */
integer i__, ix, iy;
doublereal dtemp;
/* applies a plane rotation. */
/* jack dongarra, linpack, 3/11/78. */
/* modified 12/3/93, array(1) declarations changed to array(*) */
/*< double precision dx(*),dy(*),dtemp,c,s >*/
/*< integer i,incx,incy,ix,iy,n >*/
/*< if(n.le.0)return >*/
/* Parameter adjustments */
--dy;
--dx;
/* Function Body */
if (*n <= 0) {
return 0;
}
/*< if(incx.eq.1.and.incy.eq.1)go to 20 >*/
if (*incx == 1 && *incy == 1) {
goto L20;
}
/* code for unequal increments or equal increments not equal */
/* to 1 */
/*< ix = 1 >*/
ix = 1;
/*< iy = 1 >*/
iy = 1;
/*< if(incx.lt.0)ix = (-n+1)*incx + 1 >*/
if (*incx < 0) {
ix = (-(*n) + 1) * *incx + 1;
}
/*< if(incy.lt.0)iy = (-n+1)*incy + 1 >*/
if (*incy < 0) {
iy = (-(*n) + 1) * *incy + 1;
}
/*< do 10 i = 1,n >*/
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
/*< dtemp = c*dx(ix) + s*dy(iy) >*/
dtemp = *c__ * dx[ix] + *s * dy[iy];
/*< dy(iy) = c*dy(iy) - s*dx(ix) >*/
dy[iy] = *c__ * dy[iy] - *s * dx[ix];
/*< dx(ix) = dtemp >*/
dx[ix] = dtemp;
/*< ix = ix + incx >*/
ix += *incx;
/*< iy = iy + incy >*/
iy += *incy;
/*< 10 continue >*/
/* L10: */
}
/*< return >*/
return 0;
/* code for both increments equal to 1 */
/*< 20 do 30 i = 1,n >*/
L20:
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
/*< dtemp = c*dx(i) + s*dy(i) >*/
dtemp = *c__ * dx[i__] + *s * dy[i__];
/*< dy(i) = c*dy(i) - s*dx(i) >*/
dy[i__] = *c__ * dy[i__] - *s * dx[i__];
/*< dx(i) = dtemp >*/
dx[i__] = dtemp;
/*< 30 continue >*/
/* L30: */
}
/*< return >*/
return 0;
/*< end >*/
} /* drot_ */
#ifdef __cplusplus
}
#endif
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