bsparse.BCSR

class BCSR(rowptr, cols, data, bshape=None, dtype=None, sizes=None, symmetry=None)

A sparse matrix in Compressed Sparse Row format.

The BCSR class represents a sparse matrix using three arrays:

• rowptr: contains the index of the first element of each row.

• cols: contains the column indices of each non-zero element.

• data: contains the values of each non-zero element.

Parameters:

rowptrarray_like

The index of the first element of each row.

colsarray_like

The column indices of each non-zero element.

dataarray_like

The values of each non-zero element.

bshapetuple, optional

The shape of the matrix container. If not given, it is inferred from indptr and indices.

dtypenumpy.dtype, optional

The data type of the matrix elements. If not given, it is inferred from the data array.

sizestuple[np.ndarray, np.ndarray], optional

The sizes of the blocks. If not given, they are inferred from data.

symmetrystr, optional

The symmetry of the matrix. If not given, no symmetry is assumed. This is only applicable for square matrices, where possible values are 'symmetric' and 'hermitian'. Note that when setting a symmetry, the lower triangular part of the matrix is discarded.

Examples

>>> rowptr = [0, 2, 3, 5]
>>> cols = [0, 1, 1, 2, 2]
>>> data = [i * np.eye(2) for i in range(1, 6)]
>>> bcsr = BCSR(rowptr, cols, data)
>>> bcsr
BCSR(bshape=(3, 3), bnnz=5 | shape=(6, 6), nnz=20)
>>> bcsr.toarray()
array([[1., 0., 2., 0., 0., 0.],
       [0., 1., 0., 2., 0., 0.],
       [0., 0., 3., 0., 0., 0.],
       [0., 0., 0., 3., 0., 0.],
       [0., 0., 0., 0., 5., 0.],
       [0., 0., 0., 0., 0., 5.]])

Attributes:

rowptrndarray

The index of the first element of each row.

colsndarray

The column coordinates of the non-zero elements.

datalist of ndarray, scipy.sparse, sparse.Sparse, or BSparse

The values of the non-zero elements.

shapetuple[int, int]

The shape of the equivalent dense matrix.

bshapetuple[int, int]

The block shape of the matrix.

row_sizesndarray

The sizes of the row elements.

col_sizesndarray

The sizes of the column elements.

dtypedtype

The data type of the matrix elements.

symmetrystr

The symmetry of the matrix.

nnzint

The number of non-zero elements in the matrix.

bnnzint

The number of non-zero elements in the matrix.

TBCSR

The transpose of the matrix.

HBCSR

The conjugate transpose of the matrix.

Methods

asbformat(format)	Converts the underlying matrix blocks to a given format.
astype(dtype)	Returns a copy of the matrix with a different data type.
bapply(func[, copy])	Applies a function to each matrix block.
conj()	The complex conjugate of the matrix.
conjugate()	The complex conjugate of the matrix.
copy()	Returns a copy of the matrix.
diagonal([offset])	Returns the diagonal of the matrix.
from_array(arr, sizes[, symmetry])	Creates a sparse matrix from a dense numpy.ndarray.
from_sparray(mat, sizes[, symmetry])	Creates a sparse matrix from a scipy.sparse.sparray.
save_npz(filename)	Saves the matrix as .npz archive.
toarray()	Converts the matrix to a dense numpy.ndarray.
tocoo()	Converts the matrix to BCOO format.
tocsr()	Converts the matrix to BCSR format.
todia()	Converts the matrix to BDIA format.