%
%   BESSPLT.M    Sample script file to plot some low-order Bessel Functions
%
%   This is a sample file to generate plots of the zero and first order Bessel 
%   functions - J0(x), J1(x)   and   Y0(x), Y1(x)
%             - I0(x), I1(x)   and   K0(x), K1(x)
%
%   File written by J. R. White, UMass-Lowell (original Nov. 1997)
%     --> modified slightly (Aug. 1998)
%

%
%   getting started
      clear all, close all
%
%   setup independent variable, but don't evaluate at exactly zero since some
%   of the functions have a singular point at zero
      Nx1 = 201;   x1 = linspace(eps,10,Nx1);   % range for ordinary BF function plots
      Nx2 = 201;   x2 = linspace(eps,4,Nx2);    % range for modified BF function plots
%
%   evaluate ordinary Bessel functions
      f0 = besselj(0,x1);    g0 = bessely(0,x1);
      f1 = besselj(1,x1);    g1 = bessely(1,x1);
%
%   evaluate modified Bessel functions
      F0 = besseli(0,x2);    G0 = besselk(0,x2);
      F1 = besseli(1,x2);    G1 = besselk(1,x2);
%
%   now let's plot these curves
      figure(1)
      subplot(2,2,1),plot(x1,[f0;g0]),grid
      axis([0 10 -2 2]);
      gtext('J0(x)'),gtext('Y0(x)')
      gtext('J0 and Y0 Bessel Functions')
%
      subplot(2,2,3),plot(x1,[f1;g1]),grid
      axis([0 10 -2 2]);
      gtext('J1(x)'),gtext('Y1(x)')
      gtext('J1 and Y1 Bessel Functions')
%
      subplot(1,2,2),plot(x2,[F0;F1;G0;G1]),grid
      axis([0 4 0 10]);
      gtext('I0(x)'),gtext('I1(x)'),gtext('K0(x)'),gtext('K1(x)')
      gtext('Modified Bessel Functions')
%
%   end of demo
%