bsparse.BDIA

class BDIA(offsets, data, bshape=None, dtype=None, sizes=None, symmetry=None)

A sparse matrix in DIAgonal format.

The BDIA class represents a sparse matrix using two arrays:

• offsets: the offsets of the diagonals, where zero indicates the main diagonal, positive values are above the main diagonal, and negative values are below the main diagonal.

• data: the values of the diagonals, not padded with zeros. Diagonals have varying lengths.

Parameters:

offsetsarray_like

The offsets of the block diagonals.

dataarray_like

The values of the block diagonals.

bshapetuple[int, int], optional

The shape of the matrix. If not given, it is inferred from the offsets and data.

dtypedtype, optional

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

sizestuple[array_like, array_like], optional

The sizes of the row and column elements. If not given, they are inferred from the 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

>>> import numpy as np
>>> offsets = [0, 1, -1]
>>> data = [
...     [np.array([[1, 0], [0, 2]]), np.array([[3, 0], [0, 4]])],
...     [np.array([[5, 0], [0, 6]])],
...     [np.array([[7, 0], [0, 8]])],
... ]
>>> bdia = BDIA(offsets, data)
>>> bdia
BDIA(bshape=(2, 2), bnnz=4 | shape=(4, 4), nnz=16)
>>> bdia.toarray()
array([[1, 0, 5, 0],
       [0, 2, 0, 6],
       [7, 0, 3, 0],
       [0, 8, 0, 4]])

Attributes:

offsetsndarray

The offsets of the block diagonals.

datalist of lists of ndarray, scipy.sparse, …

The values of the block diagonals. The inner lists represent the block diagonals, and the inner arrays represent the blocks.

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.

TBDIA

The transpose of the matrix.

HBDIA

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 BDIA matrix from a scipy.sparse.sparray.
save_npz(filename)	Saves the matrix as .npz archive.
toarray()	Returns a dense matrix.
tocoo()	Returns a COOrdinate representation of the matrix.
tocsr()	Returns a Compressed Sparse Row representation of the matrix.
todia()	Returns a DIAgonal representation of the matrix.