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- /* integration/qmomo.c
- *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
- *
- * 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 3 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, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- */
- #include "gsl__config.h"
- #include <stdlib.h>
- #include "gsl_integration.h"
- #include "gsl_errno.h"
- static void
- initialise (double * ri, double * rj, double * rg, double * rh,
- double alpha, double beta);
- gsl_integration_qaws_table *
- gsl_integration_qaws_table_alloc (double alpha, double beta, int mu, int nu)
- {
- gsl_integration_qaws_table * t;
- if (alpha < -1.0)
- {
- GSL_ERROR_VAL ("alpha must be greater than -1.0", GSL_EINVAL, 0);
- }
- if (beta < -1.0)
- {
- GSL_ERROR_VAL ("beta must be greater than -1.0", GSL_EINVAL, 0);
- }
- if (mu != 0 && mu != 1)
- {
- GSL_ERROR_VAL ("mu must be 0 or 1", GSL_EINVAL, 0);
- }
- if (nu != 0 && nu != 1)
- {
- GSL_ERROR_VAL ("nu must be 0 or 1", GSL_EINVAL, 0);
- }
- t = (gsl_integration_qaws_table *)
- malloc(sizeof(gsl_integration_qaws_table));
- if (t == 0)
- {
- GSL_ERROR_VAL ("failed to allocate space for qaws_table struct",
- GSL_ENOMEM, 0);
- }
- t->alpha = alpha;
- t->beta = beta;
- t->mu = mu;
- t->nu = nu;
-
- initialise (t->ri, t->rj, t->rg, t->rh, alpha, beta);
-
- return t;
- }
- int
- gsl_integration_qaws_table_set (gsl_integration_qaws_table * t,
- double alpha, double beta, int mu, int nu)
- {
- if (alpha < -1.0)
- {
- GSL_ERROR ("alpha must be greater than -1.0", GSL_EINVAL);
- }
- if (beta < -1.0)
- {
- GSL_ERROR ("beta must be greater than -1.0", GSL_EINVAL);
- }
- if (mu != 0 && mu != 1)
- {
- GSL_ERROR ("mu must be 0 or 1", GSL_EINVAL);
- }
- if (nu != 0 && nu != 1)
- {
- GSL_ERROR ("nu must be 0 or 1", GSL_EINVAL);
- }
- t->alpha = alpha;
- t->beta = beta;
- t->mu = mu;
- t->nu = nu;
-
- initialise (t->ri, t->rj, t->rg, t->rh, alpha, beta);
- return GSL_SUCCESS;
- }
- void
- gsl_integration_qaws_table_free (gsl_integration_qaws_table * t)
- {
- free (t);
- }
- static void
- initialise (double * ri, double * rj, double * rg, double * rh,
- double alpha, double beta)
- {
- const double alpha_p1 = alpha + 1.0;
- const double beta_p1 = beta + 1.0;
- const double alpha_p2 = alpha + 2.0;
- const double beta_p2 = beta + 2.0;
- const double r_alpha = pow (2.0, alpha_p1);
- const double r_beta = pow (2.0, beta_p1);
- size_t i;
-
- double an, anm1;
- ri[0] = r_alpha / alpha_p1;
- ri[1] = ri[0] * alpha / alpha_p2;
- an = 2.0;
- anm1 = 1.0;
- for (i = 2; i < 25; i++)
- {
- ri[i] = -(r_alpha + an * (an - alpha_p2) * ri[i - 1])
- / (anm1 * (an + alpha_p1));
- anm1 = an;
- an = an + 1.0;
- }
- rj[0] = r_beta / beta_p1;
- rj[1] = rj[0] * beta / beta_p2;
- an = 2.0;
- anm1 = 1.0;
- for (i = 2; i < 25; i++)
- {
- rj[i] = -(r_beta + an * (an - beta_p2) * rj[i - 1])
- / (anm1 * (an + beta_p1));
- anm1 = an;
- an = an + 1.0;
- }
- rg[0] = -ri[0] / alpha_p1;
- rg[1] = -rg[0] - 2.0 * r_alpha / (alpha_p2 * alpha_p2);
- an = 2.0;
- anm1 = 1.0;
- for (i = 2; i < 25; i++)
- {
- rg[i] = -(an * (an - alpha_p2) * rg[i - 1] - an * ri[i - 1]
- + anm1 * ri[i]) / (anm1 * (an + alpha_p1));
- anm1 = an;
- an = an + 1.0;
- }
- rh[0] = -rj[0] / beta_p1;
- rh[1] = -rh[0] - 2.0 * r_beta / (beta_p2 * beta_p2);
- an = 2.0;
- anm1 = 1.0;
- for (i = 2; i < 25; i++)
- {
- rh[i] = -(an * (an - beta_p2) * rh[i - 1] - an * rj[i - 1]
- + anm1 * rj[i]) / (anm1 * (an + beta_p1));
- anm1 = an;
- an = an + 1.0;
- }
- for (i = 1; i < 25; i += 2)
- {
- rj[i] *= -1;
- rh[i] *= -1;
- }
- }
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