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How do I integrate this set of matrix data points

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I have a matrix diffphi which is a 32x32 matrix. I want to integrate this using trapz in the following manner:
for every row namely k, I want to integrate diffphi(k,1:2) over 1:2 and , then diff(k,1:3) over 1:3, .... diff(k,1:32) over 1:32 then store all values in a new matrix called ophi which will be a 32x32 matrix. How should I do it?
Here is something that I tried:
if true
% code
end
ophi = zeros(32,32);
for h = 1:32
for d = 1:32
c = 1:d;
ophi(h,d) = trapz(c,diffphi(h,(1:d)));
end
end
But it shows the following error:
Error in ipermute (line 23) inverseorder(order) = 1:numel(order); % Inverse permutation order
Error in trapz (line 73)
Thanks in advance. if ~isempty(perm), z = ipermute(z,perm); end

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Accepted Answer

Massimo Zanetti
Massimo Zanetti on 24 Feb 2017
You just need one for loop as trapz operates also on matrices. This is the piece of code:
A = rand(32);
B = zeros(32);
for c = 1:size(A,2)
B(:,c) = trapz(1:c,A(:,1:c),2);
end
B

  2 Comments

vishav Rattu
vishav Rattu on 24 Feb 2017
I need to integrate every row, vary the indices and store it in a 32x32 matrix. But still thanks, as I modified this a bit to get to the result. I actually need 2 for loops.
Massimo Zanetti
Massimo Zanetti on 24 Feb 2017
The code above does EXACTLY what you need, it integrates every row by varying the row length and stroes everything in a 32x32 matrix B. You DON'T need two for loops.
Check carefully trapz help page.

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