Compare values of array of matrix 5x5x106

Hi!

I have a array of logical matrix 5x5x106 (attached file): I want to compare every logical matrix with the others to find common elements end save them. I try this code:

for k=1:106
if valueNoZeros(:,:,k)==valueNoZeros(:,:,k+1)
a(:,:,k)=1;
end
end

and also this

for k=1:106
if valueNoZeros(:,:,k)==valueNoZeros(:,:,k+1)
for i=1:5
for j=1:5
a(i,j,k)=1;
end 
end
end
end
but it gives me an error: 'Conversion to cell from double is not possible'
Can you help me?

Answer 1

[Thorsten]

If you want to compare every matrix with each other, you have 5565 pairs to compare:

 Npairs = nchoosek(1:106,2);
 N = size(Npairs, 1);
 A = zeros(5,5,N); 
 for i = 1:N
   A(:,:,i) = valueNoZeros(:,:,Npairs(i,1)) == valueNoZeros(:,:,Npairs(i,2)); 
 end

If you just want to compare a matrix with the following matrix, you have 105 comparisons:

 N = 106 - 1;
 for i = 1:N
   A(:,:,i) = valueNoZeros(:,:,i) == valueNoZeros(:,:,i+1); 
 end

[pamela sulis]

I have a doubt: I want to compare only the values '1' and not the '0', I modify your code in this way:

Npairs = nchoosek(1:106,2);
 N = size(Npairs, 1);
 A = zeros(5,5,N); 
 for i = 1:N
if (valueNoZeros~=0)
 A(:,:,i) = valueNoZeros(:,:,Npairs(i,1)) == valueNoZeros(:,:,Npairs(i,2)); 
 end
end

but now the comparison give me matrix of all zeros: isn't correct the command 'if (valueNoZeros~=0)'? I have thought that with this command, the code doesn't consider values '0' but only the '1'.

[Thorsten]

valueNoZeros~=0 gives an 5x5x106 logical array that is logical 1 if valueNoZeros is one (valueNoZeros~=0) else 0. So this is just the same as valueNoZeros! Moreover, it is a whole array, which is only true if all elements are true; in the example, it is never true...

So if you want A to be 1 if there is a one in two matrices, use

A(:,:,i) = valueNoZeros(:,:,Npairs(i,1)) & valueNoZeros(:,:,Npairs(i,2));