| /* |
| * R : A Computer Language for Statistical Data Analysis |
| * Copyright (C) 2006-8 The R Core Team |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, a copy is available at |
| * https://www.R-project.org/Licenses/ |
| */ |
| |
| #include "nmath.h" |
| #include "dpq.h" |
| |
| double qnf(double p, double df1, double df2, double ncp, int lower_tail, |
| int log_p) |
| { |
| double y; |
| |
| #ifdef IEEE_754 |
| if (ISNAN(p) || ISNAN(df1) || ISNAN(df2) || ISNAN(ncp)) |
| return p + df1 + df2 + ncp; |
| #endif |
| if (df1 <= 0. || df2 <= 0. || ncp < 0) ML_ERR_return_NAN; |
| if (!R_FINITE(ncp)) ML_ERR_return_NAN; |
| if (!R_FINITE(df1) && !R_FINITE(df2)) ML_ERR_return_NAN; |
| R_Q_P01_boundaries(p, 0, ML_POSINF); |
| |
| if (df2 > 1e8) /* avoid problems with +Inf and loss of accuracy */ |
| return qnchisq(p, df1, ncp, lower_tail, log_p)/df1; |
| |
| y = qnbeta(p, df1 / 2., df2 / 2., ncp, lower_tail, log_p); |
| return y/(1-y) * (df2/df1); |
| } |