sparse

Sparse matrix definition.

Syntax

• sp = sparse(M)
• sp = sparse(m, n)
• sp = sparse(I, J, V)
• sp = sparse(I, J, V, m, n)
• sp = sparse(I, J, V, m, n, nz)

Input argument

• M - a matrix: double or logical.
• m - an integer value: rows dimension.
• n - an integer value: columns dimension
• I - a vector.
• J - a vector.
• V - a vector.
• nz - an integer value: storage allocation for nonzero elements.

Output argument

• S - a single.

Description

sparse is used to build a sparse matrix. Only non-zero entries are stored.

If Mis a full matrix, sparse converts it to a sparse matrix representation, removing all zero values.

If nz is not specified, sparse uses as default value: nz = max([numel(i), numel(j), numel(v)])

If multiple values are specified with the same i, j indices, the associated value will be the sum of the values at the repeated index.

Examples

sp = sparse(eye(3,3))

sp = sparse(3, 3)

I = [1 2 3];
J = [3 1 2];
V = [32 42 53];
sp = sparse(I, J, V)
size(sp)

I = [1 2 3];
J = [3 1 2];
V = [32 42 53];
sp = sparse(I, J, V, 5, 4)
size(sp)
nnz(sp)
nzmax(sp)

I = [1 2 3];
J = [3 1 2];
V = [32 42 53];
sp = sparse(I, J, V, 5, 4, 10)
size(sp)
nnz(sp)
nzmax(sp)

See also

full, IJV, nnz, nzmax.

History

Author

Allan CORNET