# Error Using cellfun for a Matrix

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MarshallSc on 10 Jan 2022
Edited: Kevin Holly on 10 Jan 2022
I have an 81 x 81 matrix that divided it into smaller matrices:
a = rand(81,81);
n = 3*ones(1,27);
a_d = mat2cell(a,n,n)
a_d = 27×27 cell array
{3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} {3×3 double} 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Now I want to perform this operation on each of the small matrices but it gives me error:
G_x = @(x) sum((x-a_d)./(x+a_d),'all');
B_x = cellfun(G_x,a_d)
Operator '-' is not supported for operands of type 'cell'.

Error in solution (line 4)
G_x = @(x) sum((x-a_d)./(x+a_d),'all');

Simon Chan on 10 Jan 2022
Try the following:
for r = 1:27
for c = 1:27
A = a_d{r,c};
B_x{r,c} = cellfun(@(x) sum((x-A)./(x+A),'all'),num2cell(A));
end
end

Kevin Holly on 10 Jan 2022
a = rand(81,81);
n = 3*ones(1,27);
a_d = mat2cell(a,n,n);
for i = 1:27
for j = 1:27
G_x = @(x) sum((x-a_d{i,j})./(x+a_d{i,j}),'all');
B_x(i,j,:,:) = cellfun(G_x,a_d);
end
end
size(B_x)
ans = 1×4
27 27 27 27
##### 2 CommentsShowHide 1 older comment
Kevin Holly on 10 Jan 2022
a = rand(81,81);
n = 3*ones(1,27);
a_d = mat2cell(a,n,n);
for i = 1:27
for j = 1:27
G_x = @(x) sum((x-a_d{i,j})./(x+a_d{i,j}),'all');
B_x{i,j,:,:} = cellfun(G_x,a_d); %Added braces here
end
end
size(B_x)
ans = 1×2
27 27