'Writes sparse or dense array `a` to Matrix Market file-like `target`.
Parameters
target : str or file-like
Matrix Market filename (extension .mtx) or open file-like object.
a : array like
Sparse or dense 2D array.
comment : str, optional
Comments to be prepended to the Matrix Market file.
field : None or str, optional
Either \'real\', \'complex\', \'pattern\', or \'integer\'.
precision : None or int, optional
Number of digits to display for real or complex values.
symmetry : None or str, optional
Either \'general\', \'symmetric\', \'skew-symmetric\', or \'hermitian\'.
If symmetry is None the symmetry type of \'a\' is determined by its
values.'

def write(self, target, a, comment='', field=None, precision=None, symmetry=None):

    (stream, close_it) = self._open(target, 'wb')
    try:
        self._write(stream, a, comment, field, precision, symmetry)
    finally:
        if close_it:
            stream.close()
        else:
            stream.flush()
