/* TO DISPLAY A GAUSSIAN FUNCTION AS USED IN NEURAL RADIAL BASIS NETWORKS
   Author Robert John Morton YE572246C December 1997 tab = 3 spaces */

#include<stdio.h>
#include<graph.h>
#include<math.h>

double Xscale = 80,
       Yscale = 80;
int Xbias = 300,
    Ybias = 300;

void ShowCurve(double x, double y) {
   short xx = x * Xscale,
	 yy = y * Yscale;
   _setpixel(Xbias + xx, Ybias - yy);
}

ShowScale(double x1, double y1, double x2, double y2) {
   short x, y;
   _moveto(x = x1 * Xscale, y = y1 * Yscale);
   _lineto(x = x2 * Xscale, y = y2 * Yscale);
}


main() {
   double x;
   _setvideomode(_VRES16COLOR);	       //VGA 640 by 480 pixels square
   _setcolor(15);                      //bright white pixels
   for (x = -3; x < 3; x += .01)
      ShowCurve(x, 3 * exp(-(x * x)));
   _settextposition(25,1);             //for PWB termination message
   printf("GAUSSIAN FUNCTION used in neural radial basis networks.\n");
   printf("x ranges from -3 to +3  and  y = 3 * exp( -(x * x) )\n");
   printf("Press any key to quit.");
   while(!kbhit());
   _setvideomode(_TEXTC80);            //reset to normal text video
}