protected void calcModelStats(
CoxPHModel model, final double[] newCoef, final double newLoglik) {
CoxPHModel.CoxPHParameters p = model._parms;
CoxPHModel.CoxPHOutput o = model._output;
final int n_coef = o.coef.length;
final Matrix inv_hessian = new Matrix(o.hessian).inverse();
for (int j = 0; j < n_coef; ++j) {
for (int k = 0; k <= j; ++k) {
final double elem = -inv_hessian.get(j, k);
o.var_coef[j][k] = elem;
o.var_coef[k][j] = elem;
}
}
for (int j = 0; j < n_coef; ++j) {
o.coef[j] = newCoef[j];
o.exp_coef[j] = Math.exp(o.coef[j]);
o.exp_neg_coef[j] = Math.exp(-o.coef[j]);
o.se_coef[j] = Math.sqrt(o.var_coef[j][j]);
o.z_coef[j] = o.coef[j] / o.se_coef[j];
}
if (o.iter == 0) {
o.null_loglik = newLoglik;
o.maxrsq = 1 - Math.exp(2 * o.null_loglik / o.n);
o.score_test = 0;
for (int j = 0; j < n_coef; ++j) {
double sum = 0;
for (int k = 0; k < n_coef; ++k) sum += o.var_coef[j][k] * o.gradient[k];
o.score_test += o.gradient[j] * sum;
}
}
o.loglik = newLoglik;
o.loglik_test = -2 * (o.null_loglik - o.loglik);
o.rsq = 1 - Math.exp(-o.loglik_test / o.n);
o.wald_test = 0;
for (int j = 0; j < n_coef; ++j) {
double sum = 0;
for (int k = 0; k < n_coef; ++k) sum -= o.hessian[j][k] * (o.coef[k] - p.init);
o.wald_test += (o.coef[j] - p.init) * sum;
}
}
