"Avez vous une idée ?"
yes: don't do this. Read this to know why:
No matter how much beginners love to invent the idea of dynamically naming their variables, it is a slow, buggy, and obfuscated way to write code. Learn to write efficient code using indexing. You will not regret doing this.
In your case a 3D matrix might be best (if all output matrices are the same size), something like this (pseudocode):
P = 50;
mat = NaN(R,C,P);
for k = 1:P
mat(:,:,k) = your calculation here;
end
Otherwise a cell array will do the job as well.
