Z must be a matrix, not a scalar or vector

Hello,

I have run into this problem concerning a code i am writing to find a solution via the Monte Carlo method. Trying to plot my results on a meshgrid or surface, but i keep running into the Z must be a matrix issue. Can anyone spot my problem and give some advice on how to fix it?

Thanks

clear;
clc;

%--Number of simulations--%
n = 100; 
sol = linspace(0,1,n);
y = zeros(1,n);
x = zeros(1,n);

%--Plot of the circle--%
figure(1)
clf;
syms p
bc = sin (p);
bc2 = cos (p);
Range = [0 2*pi];
subplot(211);
h = ezplot(bc,bc2,[Range]);
hold on

[X,Y] = meshgrid(-1:0.1:1);

% 
Nsamples    = 5;
distance    = zeros(n,Nsamples);
circle      = zeros(n,Nsamples);
delta = 0.1;

% for loop2 = 1:Nsamples
    for t=1:n

          %--Monte Carlo Random Walk--%
          monte = randi(4,1);
          if monte == 1
              y = y + delta;
          elseif monte == 2
              y = y - delta;
          elseif monte == 3
              x = x + delta;
          elseif monte ==4
              x = x - delta;
          end

          %--Applying BC if sin is btween pi and 2pi--%
          %--Applying it by not allowing y >= 0--%
          if y < 0
              y = 0;
          end

          %--Solving for radius to see if BC's are hit--%
          radius = sqrt(x.^2 + y.^2);

          %--Calculating Theta for the BC--%
          theta = atan(y./x);

          %--Calcuating the solution with BC's--%
          if radius >= 1
              sol = sin(theta);
          elseif radius <= 0
              sol = 0;
          end

          %--Plotted walk on a circle plot--%
          subplot(211);
          plot(x,y,'.b');

          radius;

          sol;

          theta;

          %--Plotting Surface of Solution--%
          figure(2)
          mesh(X,Y,sol)

      end

Answer 1

[Mike Hosea]

It's telling you that the variable "sol" is a vector, whereas X and Y are matrices. If you want to plot a set of points on a surface, for every (X(i,j),Y(i,j)) pair the "mesh" function needs a Z(i,j), but that isn't provided by the sol vector. In fact, I don't see any connection at all between sol and the X and Y arrays.

[Mike]

Yeah, that makes sense. What i'm trying to do it plot the sol on a surface of an x and y range. That's what i thought i was doing, what would i need to change in order to do that?