spalloc

Purpose

Allocate space for sparse matrices.

Synopsis

S = spalloc(m,n,nzmax)

Description

S = spalloc(m,n,nzmax) creates an all zero sparse matrix S of size m-by-n with room to hold nzmax nonzeros. The matrix can then be generated column by column without requiring repeated storage allocation as the number of nonzeros grows.

spalloc(m,n,nzmax) is shorthand for

sparse([],[],[],m,n,nzmax)

Examples

To efficiently generate a sparse matrix which has an average of at most three nonzero elements per column

S = spalloc(n,n,3*n);
for j = 1:n
    S(:,j) = { the j-th column }
end

(c) Copyright 1994 by The MathWorks, Inc.