📄 test.c
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/* ode-initval/test_odeiv.c * * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman * * 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, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *//* Author: G. Jungman */#include <config.h>#include <stdlib.h>#include <stdio.h>#include <math.h>#include <gsl/gsl_test.h>#include <gsl/gsl_errno.h>#include <gsl/gsl_math.h>#include <gsl/gsl_matrix.h>#include <gsl/gsl_linalg.h>#include <gsl/gsl_ieee_utils.h>#include "gsl_odeiv.h"int rhs_linear (double t, const double y[], double f[], void *params);int jac_linear (double t, const double y[], double *dfdy, double dfdt[], void *params);int rhs_sin (double t, const double y[], double f[], void *params);int jac_sin (double t, const double y[], double *dfdy, double dfdt[], void *params);int rhs_exp (double t, const double y[], double f[], void *params);int jac_exp (double t, const double y[], double *dfdy, double dfdt[], void *params);int rhs_stiff (double t, const double y[], double f[], void *params);int jac_stiff (double t, const double y[], double *dfdy, double dfdt[], void *params);void test_stepper_linear (const gsl_odeiv_step_type * T, double h, double base_prec);void test_stepper_sin (const gsl_odeiv_step_type * T, double h, double base_prec);void test_stepper_exp (const gsl_odeiv_step_type * T, double h, double base_prec);void test_stepper_stiff (const gsl_odeiv_step_type * T, double h, double base_prec);void test_evolve_system_flat (gsl_odeiv_step * step, const gsl_odeiv_system * sys, double t0, double t1, double hstart, double y[], double yfin[], double err_target, const char *desc);void test_evolve_system (const gsl_odeiv_step_type * T, const gsl_odeiv_system * sys, double t0, double t1, double hstart, double y[], double yfin[], double err_target, const char *desc);void test_evolve_exp (const gsl_odeiv_step_type * T, double h, double err);void test_evolve_sin (const gsl_odeiv_step_type * T, double h, double err);void test_evolve_stiff1 (const gsl_odeiv_step_type * T, double h, double err);void test_evolve_stiff5 (const gsl_odeiv_step_type * T, double h, double err);/* RHS for a + b t */intrhs_linear (double t, const double y[], double f[], void *params){ f[0] = 0.0; f[1] = y[0]; return GSL_SUCCESS;}intjac_linear (double t, const double y[], double *dfdy, double dfdt[], void *params){ gsl_matrix dfdy_mat; dfdy_mat.size1 = 2; dfdy_mat.size2 = 2; dfdy_mat.tda = 2; dfdy_mat.data = dfdy; dfdy_mat.block = 0; gsl_matrix_set (&dfdy_mat, 0, 0, 0.0); gsl_matrix_set (&dfdy_mat, 0, 1, 0.0); gsl_matrix_set (&dfdy_mat, 1, 0, 1.0); gsl_matrix_set (&dfdy_mat, 1, 1, 0.0); dfdt[0] = 0.0; dfdt[1] = 0.0; return GSL_SUCCESS;}gsl_odeiv_system rhs_func_lin = { rhs_linear, jac_linear, 2, 0};/* RHS for sin(t),cos(t) */intrhs_sin (double t, const double y[], double f[], void *params){ f[0] = -y[1]; f[1] = y[0]; return GSL_SUCCESS;}intjac_sin (double t, const double y[], double *dfdy, double dfdt[], void *params){ gsl_matrix dfdy_mat; dfdy_mat.data = dfdy; dfdy_mat.size1 = 2; dfdy_mat.size2 = 2; dfdy_mat.tda = 2; dfdy_mat.block = 0; gsl_matrix_set (&dfdy_mat, 0, 0, 0.0); gsl_matrix_set (&dfdy_mat, 0, 1, -1.0); gsl_matrix_set (&dfdy_mat, 1, 0, 1.0); gsl_matrix_set (&dfdy_mat, 1, 1, 0.0); dfdt[0] = 0.0; dfdt[1] = 0.0; return GSL_SUCCESS;}gsl_odeiv_system rhs_func_sin = { rhs_sin, jac_sin, 2, 0};/* RHS for a exp(t)+ b exp(-t) */intrhs_exp (double t, const double y[], double f[], void *params){ f[0] = y[1]; f[1] = y[0]; return GSL_SUCCESS;}intjac_exp (double t, const double y[], double *dfdy, double dfdt[], void *params){ gsl_matrix dfdy_mat; dfdy_mat.data = dfdy; dfdy_mat.size1 = 2; dfdy_mat.size2 = 2; dfdy_mat.tda = 2; dfdy_mat.block = 0; gsl_matrix_set (&dfdy_mat, 0, 0, 0.0); gsl_matrix_set (&dfdy_mat, 0, 1, 1.0); gsl_matrix_set (&dfdy_mat, 1, 0, 1.0); gsl_matrix_set (&dfdy_mat, 1, 1, 0.0); dfdt[0] = 0.0; dfdt[1] = 0.0; return GSL_SUCCESS;}gsl_odeiv_system rhs_func_exp = { rhs_exp, jac_exp, 2, 0};/* RHS for stiff example */intrhs_stiff (double t, const double y[], double f[], void *params){ f[0] = 998.0 * y[0] + 1998.0 * y[1]; f[1] = -999.0 * y[0] - 1999.0 * y[1]; return GSL_SUCCESS;}intjac_stiff (double t, const double y[], double *dfdy, double dfdt[], void *params){ gsl_matrix dfdy_mat; dfdy_mat.data = dfdy; dfdy_mat.size1 = 2; dfdy_mat.size2 = 2; dfdy_mat.tda = 2; dfdy_mat.block = 0; gsl_matrix_set (&dfdy_mat, 0, 0, 998.0); gsl_matrix_set (&dfdy_mat, 0, 1, 1998.0); gsl_matrix_set (&dfdy_mat, 1, 0, -999.0); gsl_matrix_set (&dfdy_mat, 1, 1, -1999.0); dfdt[0] = 0.0; dfdt[1] = 0.0; return GSL_SUCCESS;}gsl_odeiv_system rhs_func_stiff = { rhs_stiff, jac_stiff, 2, 0};voidtest_stepper_linear (const gsl_odeiv_step_type * T, double h, double base_prec){ int s = 0; double y[2]; double yerr[2]; double t; double del; double delmax = 0.0; int count = 0; gsl_odeiv_step *stepper = gsl_odeiv_step_alloc (T, 2); y[0] = 1.0; y[1] = 0.0; for (t = 0.0; t < 4.0; t += h) { gsl_odeiv_step_apply (stepper, t, h, y, yerr, 0, 0, &rhs_func_lin); del = fabs ((y[1] - (t + h)) / y[1]); delmax = GSL_MAX_DBL (del, delmax); if (del > (count + 1.0) * base_prec) { printf (" LINEAR(%20.17g) %20.17g %20.17g %8.4g\n", t + h, y[1], t + h, del); s++; } count++; } gsl_test (s, "%s, linear [0,4], max relative error = %g", gsl_odeiv_step_name (stepper), delmax); gsl_odeiv_step_free (stepper);}voidtest_stepper_sin (const gsl_odeiv_step_type * T, double h, double base_prec){ int s = 0; double y[2]; double yerr[2]; double t; double del; double delmax = 0.0; int count = 0; gsl_odeiv_step *stepper = gsl_odeiv_step_alloc (T, 2); y[0] = 1.0; y[1] = 0.0; for (t = 0.0; t < M_PI; t += h) { int stat; double sin_th = sin (t + h); gsl_odeiv_step_apply (stepper, t, h, y, yerr, 0, 0, &rhs_func_sin); del = fabs ((y[1] - sin_th) / sin_th); delmax = GSL_MAX_DBL (del, delmax); { if (t < 0.5 * M_PI) { stat = (del > (count + 1.0) * base_prec); } else if (t < 0.7 * M_PI) { stat = (del > 1.0e+04 * base_prec); } else if (t < 0.9 * M_PI) { stat = (del > 1.0e+06 * base_prec); } else { stat = (del > 1.0e+09 * base_prec); } if (stat != 0) { printf (" SIN(%22.18g) %22.18g %22.18g %10.6g\n", t + h, y[1], sin_th, del); } s += stat; } count++; } if (delmax > 1.0e+09 * base_prec) { s++; printf (" SIN(0 .. M_PI) delmax = %g\n", delmax); } gsl_test (s, "%s, sine [0,pi], max relative error = %g", gsl_odeiv_step_name (stepper), delmax); delmax = 0.0; for (; t < 100.5 * M_PI; t += h) { gsl_odeiv_step_apply (stepper, t, h, y, yerr, 0, 0, &rhs_func_sin); del = fabs (y[1] - sin (t)); delmax = GSL_MAX_DBL (del, delmax); count++; } if (del > count * 2.0 * base_prec) { s++; printf (" SIN(%22.18g) %22.18g %22.18g %10.6g\n", t + h, y[1], sin (t), del); } gsl_test (s, "%s, sine [pi,100.5*pi], max absolute error = %g", gsl_odeiv_step_name (stepper), delmax); gsl_odeiv_step_free (stepper);}voidtest_stepper_exp (const gsl_odeiv_step_type * T, double h, double base_prec){ int s = 0; double y[2]; double yerr[2]; double t; double del, delmax = 0.0; int count = 0; gsl_odeiv_step *stepper = gsl_odeiv_step_alloc (T, 2); y[0] = 1.0; y[1] = 1.0; for (t = 0.0; t < 20.0; t += h) { double ex = exp (t + h); gsl_odeiv_step_apply (stepper, t, h, y, yerr, 0, 0, &rhs_func_exp); del = fabs ((y[1] - ex) / y[1]); delmax = GSL_MAX_DBL (del, delmax); if (del > (count + 1.0) * 2.0 * base_prec) { printf (" EXP(%20.17g) %20.17g %20.17g %8.4g\n", t + h, y[1], ex, del); s++; } count++; } gsl_test (s, "%s, exponential [0,20], max relative error = %g", gsl_odeiv_step_name (stepper), delmax); gsl_odeiv_step_free (stepper);}voidtest_stepper_stiff (const gsl_odeiv_step_type * T, double h, double base_prec){ int s = 0; double y[2]; double yerr[2]; double t; double del, delmax = 0.0; int count = 0; gsl_odeiv_step *stepper = gsl_odeiv_step_alloc (T, 2); y[0] = 1.0; y[1] = 0.0; for (t = 0.0; t < 20.0; t += h) { gsl_odeiv_step_apply (stepper, t, h, y, yerr, NULL, NULL, &rhs_func_stiff); if (t > 0.04) { double arg = t + h; double e1 = exp (-arg); double e2 = exp (-1000.0 * arg); double u = 2.0 * e1 - e2; /* double v = -e1 + e2; */ del = fabs ((y[0] - u) / y[0]); delmax = GSL_MAX_DBL (del, delmax); if (del > (count + 1.0) * 100.0 * base_prec) { printf (" STIFF(%20.17g) %20.17g %20.17g %8.4g\n", arg, y[0], u, del); s++; } } count++; } gsl_test (s, "%s, stiff [0,20], max relative error = %g", gsl_odeiv_step_name (stepper), delmax); gsl_odeiv_step_free (stepper);}voidtest_evolve_system_flat (gsl_odeiv_step * step, const gsl_odeiv_system * sys, double t0, double t1, double hstart, double y[], double yfin[], double err_target, const char *desc){ int s = 0; double frac; double t = t0; double h = hstart; gsl_odeiv_evolve *e = gsl_odeiv_evolve_alloc (sys->dimension); while (t < t1) { gsl_odeiv_evolve_apply (e, NULL, step, sys, &t, t1, &h, y); } frac = fabs ((y[1] - yfin[1]) / yfin[1]) + fabs ((y[0] - yfin[0]) / yfin[0]); if (frac > 2.0 * e->count * err_target) { printf ("FLAT t = %.5e y0 = %g y1= %g\n", t, y[0], y[1]); s++; } gsl_test (s, "%s, %s, evolve, no control, max relative error = %g", gsl_odeiv_step_name (step), desc, frac); gsl_odeiv_evolve_free (e);}voidtest_evolve_system (const gsl_odeiv_step_type * T, const gsl_odeiv_system * sys, double t0, double t1, double hstart, double y[], double yfin[], double err_target, const char *desc){ int s = 0; double frac; double t = t0; double h = hstart; gsl_odeiv_step * step = gsl_odeiv_step_alloc (T, sys->dimension); gsl_odeiv_control *c = gsl_odeiv_control_standard_new (0.0, err_target, 1.0, 1.0); gsl_odeiv_evolve *e = gsl_odeiv_evolve_alloc (sys->dimension); while (t < t1) { gsl_odeiv_evolve_apply (e, c, step, sys, &t, t1, &h, y); /* printf ("SYS t = %.18e h = %g y0 = %g y1= %g\n", t, h, y[0], y[1]); */ } frac = fabs ((y[1] - yfin[1]) / yfin[1]) + fabs ((y[0] - yfin[0]) / yfin[0]); if (frac > 2.0 * e->count * err_target) { printf ("SYS t = %.5e h = %g y0 = %g y1= %g\n", t, h, y[0], y[1]); s++; } gsl_test (s, "%s, %s, evolve, standard control, relative error = %g", gsl_odeiv_step_name (step), desc, frac); gsl_odeiv_evolve_free (e); gsl_odeiv_control_free (c); gsl_odeiv_step_free (step);}voidtest_evolve_exp (const gsl_odeiv_step_type * T, double h, double err){ double y[2]; double yfin[2]; y[0] = 1.0; y[1] = 1.0; yfin[0] = exp (10.0); yfin[1] = yfin[0]; test_evolve_system (T, &rhs_func_exp, 0.0, 10.0, h, y, yfin, err, "exp [0,10]");}voidtest_evolve_sin (const gsl_odeiv_step_type * T, double h, double err){ double y[2]; double yfin[2]; y[0] = 1.0; y[1] = 0.0; yfin[0] = cos (2.0); yfin[1] = sin (2.0); test_evolve_system (T, &rhs_func_sin, 0.0, 2.0, h, y, yfin, err, "sine [0,2]");}voidtest_evolve_stiff1 (const gsl_odeiv_step_type * T, double h, double err){ double y[2]; double yfin[2]; y[0] = 1.0; y[1] = 0.0; { double arg = 1.0; double e1 = exp (-arg); double e2 = exp (-1000.0 * arg); yfin[0] = 2.0 * e1 - e2; yfin[1] = -e1 + e2; } test_evolve_system (T, &rhs_func_stiff, 0.0, 1.0, h, y, yfin, err, "stiff [0,1]");}voidtest_evolve_stiff5 (const gsl_odeiv_step_type * T, double h, double err){ double y[2]; double yfin[2]; y[0] = 1.0; y[1] = 0.0; { double arg = 5.0; double e1 = exp (-arg); double e2 = exp (-1000.0 * arg); yfin[0] = 2.0 * e1 - e2; yfin[1] = -e1 + e2; } test_evolve_system (T, &rhs_func_stiff, 0.0, 5.0, h, y, yfin, err, "stiff [0,5]");}intmain (void){ int i; struct ptype { const gsl_odeiv_step_type *type; double h; } p[20]; p[0].type = gsl_odeiv_step_rk2; p[0].h = 1.0e-03; p[1].type = gsl_odeiv_step_rk2imp; p[1].h = 1.0e-03; p[2].type = gsl_odeiv_step_rk4; p[2].h = 1.0e-03; p[3].type = gsl_odeiv_step_rk4imp; p[3].h = 1.0e-03; p[4].type = gsl_odeiv_step_rkf45; p[4].h = 1.0e-03; p[5].type = gsl_odeiv_step_rk8pd; p[5].h = 1.0e-03; p[6].type = gsl_odeiv_step_rkck; p[6].h = 1.0e-03; p[7].type = gsl_odeiv_step_bsimp; p[7].h = 0.1; p[8].type = gsl_odeiv_step_gear1; p[8].h = 1.0e-03; p[9].type = gsl_odeiv_step_gear2; p[9].h = 1.0e-03; p[10].type = 0; gsl_ieee_env_setup (); for (i = 0; p[i].type != 0; i++) { test_stepper_linear (p[i].type, p[i].h, GSL_SQRT_DBL_EPSILON); test_stepper_sin (p[i].type, p[i].h / 10.0, GSL_SQRT_DBL_EPSILON); test_stepper_exp (p[i].type, p[i].h / 10.0, GSL_SQRT_DBL_EPSILON); test_stepper_stiff (p[i].type, p[i].h / 10.0, GSL_SQRT_DBL_EPSILON); } for (i = 0; p[i].type != 0; i++) { test_evolve_exp (p[i].type, p[i].h, GSL_SQRT_DBL_EPSILON); test_evolve_sin (p[i].type, p[i].h, GSL_SQRT_DBL_EPSILON); test_evolve_stiff1 (p[i].type, p[i].h, 1e-5); test_evolve_stiff5 (p[i].type, p[i].h, 1e-5); } exit (gsl_test_summary ());}
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