Simple Convolution Plot Errors

I am trying to plot a convolution example from my text book. Somewhere in the setting up of the plot dimensions/colors etc i made an error and i cannot find it. any help would be greatly appreciated.

The current compile error is on

axis ([tau (1) tau(end) -2.0 2.5]);

thank you.

% MS2p4.m : MATLAB Session 2, Program 4
% Script M-file graphically demonstrates the convolution process.
clc
clear

figure (1) % Create figure window and make visible on screen
x = inline('1.5*sin(pi*t).*(t>=0 & t<1)');
h = inline('1.5*(t>=0&t<1.5) - (t>=2&t<2.5)');
dtau = 0.005; tau = -1:dtau:4;
ti = 0; tvec = -.25:.1:3.75;
y = NaN*zeros(1, length (tvec)); % Pre-allocate memory
for t = tvec,
    ti = ti+1; % Time index
    xh = x(t-tau).*h(tau); lxh = length (xh);
    y(ti) = sum(xh.*dtau); % Trapezoidal approximation of interal
    subplot (2,1,1), plot(tau, h(tau), 'k-', tau, x(t-tau), 'k--', t, 0, 'ok');
    axis ([tau (1) tau(end) -2.0 2.5]);
    patch([tau(1:end-1); tau(1:end-1); tau (2:end); tau (2:end)],...
    [zeros(1,lxh-1);xh(1:end-1);xh(2:end);zeros(1,lxh-1)],...
    [.8 .8 .8], 'edgecolor', 'none');

      c = get(gca, 'children'); set (gca, 'children', [c(2); c(3); c(4); c(1)]);
      subplot (2, 1, 2), plot (tvec, y, 'k', tvec (ti), y(ti), 'ok');
      xlabel ('t'); ylabel ('y(t) = \int h(\tau)x(t-\tau) d\tau');
      axis ([tau(1) tau(end) -1.0 2.0]); grid;
      drawnow;
      axis ([tau(1) tau(end) -1.0 2.0]); grid;
      drawnow;
  end

Answer 1

[Image Analyst]

You have a space between tau and (1) and (2:end), so it thinks there are two separate things, and then you end up having more than 4 elements in between the brackets. Get rid of that space. Fixed code:

    axis ([tau(1) tau(end) -2.0 2.5]);
    patch([tau(1:end-1); tau(1:end-1); tau(2:end); tau(2:end)],...
    [zeros(1,lxh-1);xh(1:end-1);xh(2:end);zeros(1,lxh-1)],...
    [.8 .8 .8], 'edgecolor', 'none');

[Anonomous]

thank you very much

[Haribabu Kilari]

Thank you so much