scipy.sparse.dia_matrix

class scipy.sparse.dia_matrix(arg1, shape=None, dtype=None, copy=False)

Sparse matrix with DIAgonal storage

This can be instantiated in several ways:

dia_matrix(D)

with a dense matrix

dia_matrix(S)

with another sparse matrix S (equivalent to S.todia())

dia_matrix((M, N), [dtype])

to construct an empty matrix with shape (M, N), dtype is optional, defaulting to dtype=’d’.

dia_matrix((data, offsets), shape=(M, N))

where the data[k,:] stores the diagonal entries for diagonal offsets[k] (See example below)

Notes

Sparse matrices can be used in arithmetic operations: they support addition, subtraction, multiplication, division, and matrix power.

Examples

>>> from scipy.sparse import *
>>> from scipy import *
>>> dia_matrix( (3,4), dtype=int8).todense()
matrix([[0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 0, 0]], dtype=int8)

>>> data = array([[1,2,3,4]]).repeat(3,axis=0)
>>> offsets = array([0,-1,2])
>>> dia_matrix( (data,offsets), shape=(4,4)).todense()
matrix([[1, 0, 3, 0],
        [1, 2, 0, 4],
        [0, 2, 3, 0],
        [0, 0, 3, 4]])

Attributes

dtype
shape
ndim	int(x[, base]) -> integer
nnz	number of nonzero values

data	DIA format data array of the matrix
offsets	DIA format offset array of the matrix

Methods

asformat(format)	Return this matrix in a given sparse format
asfptype()	Upcast matrix to a floating point format (if necessary)
astype(t)
conj()
conjugate()
copy()
diagonal()	Returns the main diagonal of the matrix
dot(other)
getH()
get_shape()
getcol(j)	Returns a copy of column j of the matrix, as an (m x 1) sparse
getformat()
getmaxprint()
getnnz()	number of nonzero values
getrow(i)	Returns a copy of row i of the matrix, as a (1 x n) sparse
mean([axis])	Average the matrix over the given axis.
multiply(other)	Point-wise multiplication by another matrix
nonzero()	nonzero indices
reshape(shape)
set_shape(shape)
setdiag(values[, k])	Fills the diagonal elements {a_ii} with the values from the given sequence.
sum([axis])	Sum the matrix over the given axis.
toarray()
tobsr([blocksize])
tocoo()
tocsc()
tocsr()
todense()
todia([copy])
todok()
tolil()
transpose()