How to assign gaussian random numbers on meshgrid?

Hi,

I have very simple problem regarding assigning gaussian or uniform random numbers, and zeros on each of the meshgrid points. I tried with following way

nx=6;
ny=6;
[x,y]=meshgrid(1:nx,1:ny);
M=[x(:),y(:);zeros(nx,ny)]; 
M=[x(:),y(:);normrnd(nx,ny)];

However, it does not work. I am missing the correct syntax. Could anyone help me to rectify it?

Answer 1

[Star Strider]

Try this:

nx=6;
ny=6;
[x,y]=meshgrid(1:nx,1:ny);
zg = randn(size(x));                            % Gaussian Random Numbers
zu = rand(size(x));                              % Uniform Random Numbers

figure(1)
surf(x,y,zg)
grid on
title('Gaussian Random Numbers')

figure(2)
surf(x,y,zu)
grid on
title('Uniform Random Numbers')

[Sudipta Sinha]

Thanks for your response. But my problem is different.I need to assign a random number or a constant number at each of the location of the meshgrid, M. For example

M(1,1)=rand1 M(1,2)=rand2 .... like that

I don't need to draw any figure with the data.

[Star Strider]

The figures are simply to demonstrate the code.

The ‘zg’ and ‘zu’ arrays are the assignments you want.

Answer 2

[Walter Roberson]

You have

nx=6;
ny=6;
[x,y]=meshgrid(1:nx,1:ny);

After that, x and y are going to be 6 x 6.

Then you have

M=[x(:),y(:);zeros(nx,ny)];

The x(:) part is going to reshape the 6 x 6 x array into (6*6) x 1 . The y(:) is going to reshape the 6 x 6 y array into (6*6) x 1. The x(:),y(:) is therefore going to be 36 x 2

The zeros(nx,ny) is going to be 6 x 6.

Now, you are using ";" between those parts, so you are trying to put the 6 x 6 array "below" the 36 x 2 array.

If you need an array with x and y and z coordinates for some reason, then I would suggest

M=[x(:), y(:), zeros(nx*ny, 1)];

[Sudipta Sinha]

No, it does not work. I need very simple thing. For each location of a grid point, I want to assign zero or random numbers. For example, if I wish to assign a value of a function (say, f=xy ) on each of the grid points, I need perform a very simple operation like f=x.*y. The dimension of the matrix, f, is defined by the dimension of x and y. However, how to pass the x and y information for generating correct dimension of zero and random numbers on each of the grid points.