zdotu.c

来自「算断裂的」· C语言 代码 · 共 83 行

/*  -- translated by f2c (version 19940927).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* Double Complex */ VOID zdotu_(doublecomplex * ret_val, integer *n, 
	doublecomplex *zx, integer *incx, doublecomplex *zy, integer *incy)
{
    /* System generated locals */
    integer i__1, i__2, i__3;
    doublecomplex z__1, z__2;

    /* Local variables */
    static integer i;
    static doublecomplex ztemp;
    static integer ix, iy;


/*     forms the dot product of two vectors.   
       jack dongarra, 3/11/78.   
       modified 12/3/93, array(1) declarations changed to array(*)   

    
   Parameter adjustments */
    --zy;
    --zx;

    /* Function Body */
    ztemp.r = 0., ztemp.i = 0.;
     ret_val->r = 0.,  ret_val->i = 0.;
    if (*n <= 0) {
	return ;
    }
    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 <= *n; ++i) {
	i__2 = ix;
	i__3 = iy;
	z__2.r = zx[ix].r * zy[iy].r - zx[ix].i * zy[iy].i, z__2.i = 
		zx[ix].r * zy[iy].i + zx[ix].i * zy[iy].r;
	z__1.r = ztemp.r + z__2.r, z__1.i = ztemp.i + z__2.i;
	ztemp.r = z__1.r, ztemp.i = z__1.i;
	ix += *incx;
	iy += *incy;
/* L10: */
    }
     ret_val->r = ztemp.r,  ret_val->i = ztemp.i;
    return ;

/*        code for both increments equal to 1 */

L20:
    i__1 = *n;
    for (i = 1; i <= *n; ++i) {
	i__2 = i;
	i__3 = i;
	z__2.r = zx[i].r * zy[i].r - zx[i].i * zy[i].i, z__2.i = 
		zx[i].r * zy[i].i + zx[i].i * zy[i].r;
	z__1.r = ztemp.r + z__2.r, z__1.i = ztemp.i + z__2.i;
	ztemp.r = z__1.r, ztemp.i = z__1.i;
/* L30: */
    }
     ret_val->r = ztemp.r,  ret_val->i = ztemp.i;
    return ;
} /* zdotu_ */