# fastest way to apply A\B on each matrix page

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hosein Javan on 17 Aug 2020
Commented: hosein Javan on 17 Aug 2020
I would like to find an efficient fast way for calculating:
for i = 1:n
X(:,:,i) = A(:,:,i)\B(:,:,i)
end
where A and B are 10*10*n, and 10*1*n size matrices respectively. the matrices are large and must be called meny times. therefore I was thinking of replacing "for loops" with a faster way that does it very fast and not iteratively.

Bruno Luong on 17 Aug 2020
Edited: Bruno Luong on 17 Aug 2020
Why insist on ARRAYFUN, your for-loop is perfectly fine. ARRAYFUN is a "vectoriztion" scam.
n = 100;
A = rand(10,10,n);
B = rand(10,1,n);
X = arrayfun(@(p) A(:,:,p)\B(:,:,p), 1:n, 'unif', 0);
X = cat(3,X{:});
hosein Javan on 17 Aug 2020
I studied your MultiSolver. it was using concatenation diagonally and make a sparse matrix as I said. I see there's no better way. however ur using of repmat and rehsape was something speedy to extract unknowns without loops. I accept your answer. thanks, but I'd like to mention once more that it was misunderstanding. please don't use words like "big scam". thanks again.