spalloc (MATLAB Functions)

Allocate space for sparse matrix

Syntax

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

S = spalloc(n,n,3*n);
for j = 1:n
    S(:,j) = [zeros(n-3,1)' round(rand(3,1))']';
end

soundsc sparse