+ // compute folded variant probability
+ for (k = 0, sum = 0.; k <= ma->M; ++k)
+ sum += (long double)(phi[k] + phi[ma->M - k]) / 2. * ma->z[k];
+ for (k = 1, sum2 = 0.; k < ma->M; ++k)
+ sum2 += (long double)(phi[k] + phi[ma->M - k]) / 2. * ma->z[k];
+ *p_var_folded = sum2 / sum;
+ *p_ref_folded = (phi[k] + phi[ma->M - k]) / 2. * (ma->z[ma->M] + ma->z[0]) / sum;
+ // the expected frequency