How do I integrate this set of matrix data points

Question

vishav Rattu 2017-2-24

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编辑： Massimo Zanetti 2017-2-24

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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Answer 1

Massimo Zanetti 2017-2-24

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在 MATLAB Online 中打开

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

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vishav Rattu 2017-2-24

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 2017-2-24

编辑：Massimo Zanetti 2017-2-24

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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