# Sparse utilities¶

A chainer.Variable can be converted into a sparse matrix in e.g. COO (Coordinate list) format. A sparse matrix stores the same data as the original object but with a different internal representation, optimized for efficient operations on sparse data, i.e. data with many zero elements.

Following are a list of supported sparse matrix formats and utilities for converting between a chainer.Variable and these representations.

Note

Please be aware that only certain functions accept sparse matrices as inputs, such as chainer.functions.sparse_matmul().

 chainer.utils.CooMatrix A sparse matrix in COO format. chainer.utils.to_coo Returns a single or a batch of matrices in COO format.