/* nag_1d_quad_wt_cauchy_1 (d01sqc) Example Program. * * Copyright 1998 Numerical Algorithms Group. * * Mark 5, 1998. * Mark 6 revised, 2000. * Mark 7 revised, 2001. * */ #include #include #include #include #ifdef __cplusplus extern "C" { #endif static double NAG_CALL g(double x, Nag_User *comm); #ifdef __cplusplus } #endif int main(void) { Integer exit_status = 0; double a, b, c; double epsabs, abserr, epsrel, result; Nag_QuadProgress qp; Integer max_num_subint; NagError fail; Nag_User comm; INIT_FAIL(fail); printf("nag_1d_quad_wt_cauchy_1 (d01sqc) Example Program Results\n"); epsabs = 0.0; epsrel = 0.0001; a = -1.0; b = 1.0; c = 0.5; max_num_subint = 200; /* nag_1d_quad_wt_cauchy_1 (d01sqc). * One-dimensional adaptive quadrature, weight function * 1/(x-c), Cauchy principal value, thread-safe */ nag_1d_quad_wt_cauchy_1(g, a, b, c, epsabs, epsrel, max_num_subint, &result, &abserr, &qp, &comm, &fail); printf("a - lower limit of integration = %10.4f\n", a); printf("b - upper limit of integration = %10.4f\n", b); printf("epsabs - absolute accuracy requested = %11.2e\n", epsabs); printf("epsrel - relative accuracy requested = %11.2e\n\n", epsrel); printf("c - parameter in the weight function = %11.2e\n", c); if (fail.code != NE_NOERROR) printf("Error from nag_1d_quad_wt_cauchy_1 (d01sqc) %s\n", fail.message); if (fail.code != NE_INT_ARG_LT && fail.code != NE_2_REAL_ARG_EQ && fail.code != NE_ALLOC_FAIL && fail.code != NE_NO_LICENCE) { printf("result - approximation to the integral = %9.2f\n", result); printf("abserr - estimate of the absolute error = %11.2e\n", abserr); printf("qp.fun_count - number of function evaluations = %4ld\n", qp.fun_count); printf("qp.num_subint - number of subintervals used = %4ld\n", qp.num_subint); /* Free memory used by qp */ NAG_FREE(qp.sub_int_beg_pts); NAG_FREE(qp.sub_int_end_pts); NAG_FREE(qp.sub_int_result); NAG_FREE(qp.sub_int_error); } else { exit_status = 1; goto END; } END: return exit_status; } static double NAG_CALL g(double x, Nag_User *comm) { double aa; aa = 0.01; return 1.0/(x*x+aa*aa); }