#include <stdio.h>
#include "neural-nets-ode.h"

// The name of the array of coords in the Matlab script
#define NN	"NN_plot_with_matlab"

/* Writes a Matlab script to plot the solution sampled at n+1 equally
 * spaced points x[0] = a, x[1], x[2], ..., x[n] on the interval [a,b].
 * The distance between a pair consecutive points is (b-a)/n.
 *
 * If the script is named file.m, then execute it in Matlab by
 * entering the command
 *     run('/path/to/file.m')
 * or, if the file is located in the current directory, simply say
 *     file
*/
void Neural_Net_plot_with_matlab(struct Neural_Net_ODE *nn, int n,
		char *outfile)
{
	double a = nn->a;
	double b = nn->b;
	FILE *fp;

	if ((fp = fopen(outfile, "w")) == NULL) {
		fprintf(stderr, "unable to open file `%s' for writing\n",
				outfile);
		return;
	}

	fprintf(fp, "close all\n");
	fprintf(fp, "%s = [ ", NN);
	for (int i = 0; i <= n; i++) {
		double x = a + (b-a)/n*i;
		Neural_Net_phi(nn, x);
		Neural_Net_eval(nn, x);
		double y = nn->N[0] * nn->phi[0];
		fprintf(fp, "%g, %g; ", x, y);
	}
	fprintf(fp, "];\n");
	fprintf(fp, "plot(%s(:,1),  %s(:,2), 'r');\n", NN, NN);
	fprintf(fp, "title({'hidden units = %d, training points = %d'",
			nn->q, nn->nu);

	if (nn->exact_sol != NULL)
		fprintf(fp, ", 'error vs exact = %g'",
				Neural_Net_error_vs_exact(nn, n));
	fprintf(fp, "});\n");
	fprintf(fp, "grid on;\n");

	fclose(fp);
}
#undef NN