MATLAB Function Reference    
speye

Sparse identity matrix

Syntax

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.

See Also
spalloc Allocate space for sparse matrix

spones Replace nonzero sparse matrix elements with ones

spdiags Extract and create sparse band and diagonal matrices

sprand Sparse uniformly distributed random matrix

sprandn Sparse normally distributed random matrix


 spdiags spfun