/* nag_2d_spline_eval (e02dec) Example Program. * * Copyright 1991 Numerical Algorithms Group. * * Mark 2, 1991. * Mark 8 revised, 2004. */ #include #include #include #include int main(void) { Integer exit_status = 0, i, m; NagError fail; Nag_2dSpline spline; double *ff = 0, *x = 0, *y = 0; INIT_FAIL(fail); /* Initialise spline */ spline.lamda = 0; spline.mu = 0; spline.c = 0; printf("nag_2d_spline_eval (e02dec) Example Program Results\n"); scanf("%*[^\n]"); /* Skip heading in data file */ /* Read m, the number of spline evaluation points. */ scanf("%ld", &m); if (m >= 1) { if (!(x = NAG_ALLOC(m, double)) || !(y = NAG_ALLOC(m, double)) || !(ff = NAG_ALLOC(m, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } } else { printf("Invalid m.\n"); exit_status = 1; return exit_status; } /* Read nx and ny, the number of knots in the x and y directions. */ scanf("%ld%ld", &(spline.nx), &(spline.ny)); if (spline.nx >= 8 && spline.ny >= 8) { if (!(spline.c = NAG_ALLOC((spline.nx-4)*(spline.ny-4), double)) || !(spline.lamda = NAG_ALLOC(spline.nx, double)) || !(spline.mu = NAG_ALLOC(spline.ny, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } } else { printf("Invalid spline.nx or spline.ny.\n"); exit_status = 1; return exit_status; } /* read the knots lamda[0] .. lamda[nx-1] and mu[0] .. mu[ny-1]. */ for (i = 0; i < spline.nx; i++) scanf("%lf", &(spline.lamda[i])); for (i = 0; i < spline.ny; i++) scanf("%lf", &(spline.mu[i])); /* Read c, the bicubic spline coefficients. */ for (i = 0; i < (spline.nx-4)*(spline.ny-4); scanf("%lf", &(spline.c[i])), i++) ; /* Read the x and y co-ordinates of the evaluation points. */ for (i = 0; i < m; i++) scanf("%lf%lf", &x[i], &y[i]); /* Evaluate the spline at the m points. */ /* nag_2d_spline_eval (e02dec). * Evaluation of bicubic spline, at a set of points */ nag_2d_spline_eval(m, x, y, ff, &spline, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_2d_spline_eval (e02dec).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print the results. */ printf(" i x[i] y[i] ff[i]\n"); for (i = 0; i < m; i++) printf("%7ld %11.3f%11.3f%11.3f\n", i, x[i], y[i], ff[i]); NAG_FREE(spline.lamda); NAG_FREE(spline.mu); NAG_FREE(spline.c); END: if (x) NAG_FREE(x); if (y) NAG_FREE(y); if (ff) NAG_FREE(ff); return exit_status; }