scipy.io.

mmread

scipy.io.mmread(source)

Reads the contents of a Matrix Market file-like ‘source’ into a matrix.

Parameters:

sourcestr or file-like

Matrix Market filename (extensions .mtx, .mtz.gz) or open file-like object.

Returns:

andarray or coo_matrix

Dense or sparse matrix depending on the matrix format in the Matrix Market file.

Notes

Changed in version 1.12.0: C++ implementation.

Examples

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>>> from io import StringIO
>>> from scipy.io import mmread

>>> text = '''%%MatrixMarket matrix coordinate real general
...  5 5 7
...  2 3 1.0
...  3 4 2.0
...  3 5 3.0
...  4 1 4.0
...  4 2 5.0
...  4 3 6.0
...  4 4 7.0
... '''

mmread(source) returns the data as sparse matrix in COO format.

>>> m = mmread(StringIO(text))
>>> m
<COOrdinate sparse matrix of dtype 'float64'
    with 7 stored elements and shape (5, 5)>
>>> m.toarray()
array([[0., 0., 0., 0., 0.],
       [0., 0., 1., 0., 0.],
       [0., 0., 0., 2., 3.],
       [4., 5., 6., 7., 0.],
       [0., 0., 0., 0., 0.]])

This method is threaded. The default number of threads is equal to the number of CPUs in the system. Use threadpoolctl to override:

>>> import threadpoolctl
>>>
>>> with threadpoolctl.threadpool_limits(limits=2):
...     m = mmread(StringIO(text))

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