opencv/3rdparty/lapack/daxpy.c

95 lines
1.8 KiB
C

#include "clapack.h"
/* Subroutine */ int daxpy_(integer *n, doublereal *da, doublereal *dx,
integer *incx, doublereal *dy, integer *incy)
{
/* System generated locals */
integer i__1;
/* Local variables */
integer i__, m, ix, iy, mp1;
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* constant times a vector plus a vector. */
/* uses unrolled loops for increments equal to one. */
/* jack dongarra, linpack, 3/11/78. */
/* modified 12/3/93, array(1) declarations changed to array(*) */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* Parameter adjustments */
--dy;
--dx;
/* Function Body */
if (*n <= 0) {
return 0;
}
if (*da == 0.) {
return 0;
}
if (*incx == 1 && *incy == 1) {
goto L20;
}
/* code for unequal increments or equal increments */
/* not equal to 1 */
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__) {
dy[iy] += *da * dx[ix];
ix += *incx;
iy += *incy;
/* L10: */
}
return 0;
/* code for both increments equal to 1 */
/* clean-up loop */
L20:
m = *n % 4;
if (m == 0) {
goto L40;
}
i__1 = m;
for (i__ = 1; i__ <= i__1; ++i__) {
dy[i__] += *da * dx[i__];
/* L30: */
}
if (*n < 4) {
return 0;
}
L40:
mp1 = m + 1;
i__1 = *n;
for (i__ = mp1; i__ <= i__1; i__ += 4) {
dy[i__] += *da * dx[i__];
dy[i__ + 1] += *da * dx[i__ + 1];
dy[i__ + 2] += *da * dx[i__ + 2];
dy[i__ + 3] += *da * dx[i__ + 3];
/* L50: */
}
return 0;
} /* daxpy_ */