speye (MATLAB Function Reference)

Sparse identity matrix

Syntax

S = speye(m,n)
S = speye(n)

Description

S = speye(m,n)

forms an m-by-n sparse matrix with 1s on the main diagonal.

S = speye(n)

abbreviates speye(n,n).

Examples

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.