??? Error using ==> mtimes Inner matrix dimensions must agree.

hi I want to draw the graph below. Unfortunately I keep getting the error message:

??? Error using ==> mtimes Inner matrix dimensions must agree. my script is:

    close all
    clear all
    clc

    N = 100;
    LW11 = [0.3 -.7;-.2 .5];
    b1 = [.1 .2];
    LW21 = [.1 -.2];
    b2 = [.3];
    for i = 1:N
        q = i * 2 / N;
        r = i / N;
        p = [q r];
        k = p';
        a = LW11 * k;
        m = a';
        b = m + b1;
        c = tansig(b);
        f = c';
        d = LW21 * f;
        e = d + b2;
        y = purelin(e);
    end
    mesh(y)
    xlabel('x')
    ylabel('y')
    zlabel('z')

pureline returns matrix, but ??? please help me

[Adam]

tansig is a function in the Neural Network Toolbox so far as I can see so I have no idea what it returns.

[Guillaume]

You left out a crucial bit of the error message: which line it occurs on. Rather than leaving it for us to guess, can you paste the whole of the red error message.

Have you looked at the size of the two matrices you're multiplying just before the error occur? Do their inner dimensions agree?

See Debugging for ways to find out yourself what went wrong.

[Greg Heath]

tansig(x) = tanh(x)

[Greg Heath]

enter the command

 whos

to determine the size of all the variables