MATLAB: Visualizing values in a matrix

pcolorvisualize mesh

Hi there,
I wrote a script that runs loops on a 100×100 matrix and changes values within. That matrix only contains ZEROS and ONES and I would like to visualize the development of the ONES for each iteration.
From what I gathered, I 'pcolor' is the way to go but I am not at all sure how to implement that.
Lets say it is only a 10×10 matrix, like so:
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0
0 0 0 0 0 0 0 0 0 0
I would like to turn this into something like this:
The numbers for row and column are not needed and neither is the outer border…
I am sure it turns out to be a simple one-liner … So, if anyone of you know how, please help.
Your help is much appreciated!!!

Best Answer

Read about spy
clc; clear all ;
m = 10 ; 
A = zeros(m);
% introduce random ones 
id = randperm(m*m,20) ; 
A(id) = 1 ;  
[m,n] = size(A) ; 
[Y,X] = meshgrid(1:m,1:n) ; 
idx = find(A) ; 
plot(X(idx),Y(idx),'s','edgecolor','r')
You can use scatter to plot squares with colors.
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