slarnv.c

来自「最著名最快的分子模拟软件」· C语言 代码 · 共 56 行

#include <math.h>
#include "gmx_lapack.h"

void
F77_FUNC(slarnv,SLARNV)(int *idist, 
	int *iseed, 
	int *n, 
	float *x)
{
    int i__1, i__2, i__3;

    int i__;
    float u[128];
    int il, iv, il2;

    --x;
    --iseed;

    i__1 = *n;
    for (iv = 1; iv <= i__1; iv += 64) {
	i__2 = 64, i__3 = *n - iv + 1;
	il = (i__2<i__3) ? i__2 : i__3;
	if (*idist == 3) {
	    il2 = il << 1;
	} else {
	    il2 = il;
	}

	F77_FUNC(slaruv,SLARUV)(&iseed[1], &il2, u);

	if (*idist == 1) {

	    i__2 = il;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		x[iv + i__ - 1] = u[i__ - 1];
	    }
	} else if (*idist == 2) {

	    i__2 = il;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		x[iv + i__ - 1] = u[i__ - 1] * 2. - 1.;
	    }
	} else if (*idist == 3) {

	    i__2 = il;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		x[iv + i__ - 1] = sqrt(log(u[(i__ << 1) - 2]) * -2.) * 
		  cos(u[(i__ << 1) - 1] * 
		      (float)6.2831853071795864769252867663);
	    }
	}
    }
    return;

}