Files
lammps/lib/linalg/drot.cpp

46 lines
1.0 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
int drot_(integer *n, doublereal *dx, integer *incx, doublereal *dy, integer *incy, doublereal *c__,
doublereal *s)
{
integer i__1;
integer i__, ix, iy;
doublereal dtemp;
--dy;
--dx;
if (*n <= 0) {
return 0;
}
if (*incx == 1 && *incy == 1) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
dtemp = *c__ * dx[i__] + *s * dy[i__];
dy[i__] = *c__ * dy[i__] - *s * dx[i__];
dx[i__] = dtemp;
}
} else {
ix = 1;
iy = 1;
if (*incx < 0) {
ix = (-(*n) + 1) * *incx + 1;
}
if (*incy < 0) {
iy = (-(*n) + 1) * *incy + 1;
}
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
dtemp = *c__ * dx[ix] + *s * dy[iy];
dy[iy] = *c__ * dy[iy] - *s * dx[ix];
dx[ix] = dtemp;
ix += *incx;
iy += *incy;
}
}
return 0;
}
#ifdef __cplusplus
}
#endif