Code optimization

Given:
- The size sz of a matrix A (sz=size(A))
- A dimension in this matrix d (1<=d<=length(sz))
- An index in this dimension i (1<=i<=sz(d))

My function "hyperplane" returns the indices I of elements in A that
lie in the "hyperplane" perpendicular to dimension d through the index
i. The code below is an implementation of this algorithm. My question
is how to calculate I without having to construct A.

Thank you
Christophe Lauwerys

%%%%%%%%%%%%%%%%

I = hyperplane(sz,d,i)

A = zeros(sz);
nd = length(sz); % number of dimensions
if i>sz(d), error('I must be smaller or equal to SZ(D)'); end

pm=circshift((1:nd)',-d+1);
Ap = permute(A,pm);
Ap(i,:)=1;
A=ipermute(Ap,pm);
I = find(A);

%%%%%%%%%%%%%%%%

.

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