clear all;clc
N = 15;
for ii = 1:N
for jj = 1:N
B
{ii
,jj
} = rand(N
,N
,N
,N
); end
end
tic
rB = reshape(cat(5,B{:}),numel(A),[]).';
out1 = reshape(rB*A(:),size(B));
toc
tic
rB = cellfun( @(x) x(:).', B, 'uni', 0 ); %'
rB = vertcat(rB{:});
dummy = reshape(rB * A(:), size(B) );
toc
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