%SPEYE  Sparse identity matrix.
%   SPEYE(M,N) and SPEYE([M N]) form an M-by-N sparse 
%   matrix with 1's on the main diagonal.  SPEYE(N) 
%   abbreviates SPEYE(N,N).
%
%   SPEYE(SIZE(A)) is a space-saving SPARSE(EYE(SIZE(A)))
%   if A is a 2-D matrix.
%
%   See also SPONES, SPDIAGS, SPALLOC, SPRAND, SPRANDN.

%   Copyright 1984-2013 The MathWorks, Inc. 
%   Built-in function.

