/* -*-ePiX-*- */
/* weierstrass.xp -- April 02, 2003 */
#include <epix.h>
using namespace ePiX;

const int N = 8; // Number of summands

/* "cb" is the Charlie Brown function, see functions.cc */

double weierstrass(double t)
{
  double y=0;
  for(int i=0; i < N; ++i)
    y += pow(2,-i)*cb(pow(2,i)*t);

  return y;
}

main() {

  bounding_box(P(-2, -0.5), P(2, 1.5));
  picture(300, 150);
  unitlength("0.015in");

  begin();

  h_axis(8);
  v_axis(4);

  h_axis_masklabels(x_size, P(0,-4), b);
  
  blue();
  plot(cb, x_min - 0.25, x_max+0.25, 4*x_size + 2);

  bold();
  black();
  plot(weierstrass, x_min, x_max, pow(2,N));

  red();
  plot(weierstrass, 0.5, 1.5, pow(2,N-2));

  end();
}