#include <math.h>
#define LD 100

extern double v1[LD], v2[LD];
extern double a1[LD][LD], a2[LD][LD];
extern double hlg2pi;
extern double uquaf(int n, double *x, double *a, int lda);


gaua(int k, double *amu, double *h, int ldh, double *x1, double *x2)
{
   urnmvn(k,a1,LD,v1);
   uvadd(k,amu,v1,x1);
   uvsub(k,amu,v1,x2);
}


gau(int k, double *amu, double *h, int ldh, double *x1, double *x2)
/* generates two antithetic random vectors x1 and x2 */
{
   dlftds(k,h,ldh,a1,LD);
   dlinrt(k,a1,LD,2,a1,LD);
   gaua(k,amu,h,ldh,x1,x2);
}


double gauk(int k, double *amu, double *h, int ldh, double *x)
{
   double d;
   uvsub(k,x,amu,v1);
   return(-uquaf(k,v1,h,ldh)/2);
}   
 

double gaun(int k, double *h, int ldh)
{
    int i;
    double aa=0.0, bb;
    dlftds(k,h,ldh,a1,LD);
    for (i=0; i<=k-1; i++)
       aa=aa+log(a1[i][i]);
    return(-k*hlg2pi+aa);
}