S = speye(m,n)
S = speye(n)
S = speye(m,n) forms an m-by-n sparse matrix with 1s on the main diagonal.
S = speye(n) abbreviates speye(n,n).
I = speye(1000) forms the sparse representation of the 1000-by-1000 identity matrix, which requires only about 16 kilobytes of storage. This is the same final result as I = sparse(eye(1000,1000)), but the latter requires eight megabytes for temporary storage for the full representation.
spalloc,spones
(c) Copyright 1994 by The MathWorks, Inc.