NOTE: you probably don't want to use this anymore. MATLAB's JIT can now do just as good a job (if not better) as the in place version without using nasty undocumented APIs.
This is a MATLAB C mex program to multiply two "sheets" (3D arrays) together. Eg:
for i=1:N
P(:,i) = A'*R(:,:,i);
endwhere all arrays are the appropriate size.
sheetmult creates a new array for the resulting product, however there is an
in-place version (sheetmultip) which places the result back in the A
matrix. This uses some undocumented features of MATLAB to work well with the
copy-on-write mechanism so, due to the nature of these APIs, this may break in
future versions or crash MATLAB. (Tested on 2014a)