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/* SCCS @(#)coxph_wtest.c   1.1 10/28/98
** C wrapper for the Cholesky-based Wald test routine
*/
#include "survS.h"
#include "survproto.h"

void coxph_wtest(int *nvar2, int *ntest, double *var, double *b,
         double *solve, double *tolerch) {
    int i,j;
    int nvar, df;
    double sum;
    double **var2;
    double *b2;

    nvar = *nvar2;      /* create a non-pointer version of nvar */
    var2 = dmatrix(var, nvar, nvar); /*make ragged array version of matrix */
    b2 = b;

    cholesky2(var2, nvar, *tolerch);
    df=0;
    for (i=0; i<nvar; i++) if (var2[i][i] >0) df++;  /* count up the df */

    for (i=0; i< *ntest; i++) {
    for (j=0; j<nvar; j++) solve[j] = b[j];
    chsolve2(var2, nvar, solve);   /*solve now has b* var-inverse */

    sum =0;
    for (j=0; j<nvar; j++) sum += b[j]*solve[j];
    b2[i] = sum;                     /* save the result */
    b += nvar;    /*move to next column of b */
    solve += nvar;
        }
    *nvar2 = df;
    }