# scipy.sparse.dia_matrix¶

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

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

```>>> import numpy as np
>>> from scipy.sparse import dia_matrix
>>> dia_matrix((3, 4), dtype=np.int8).toarray()
array([[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]], dtype=int8)
```
```>>> data = np.array([[1, 2, 3, 4]]).repeat(3, axis=0)
>>> offsets = np.array([0, -1, 2])
>>> dia_matrix((data, offsets), shape=(4, 4)).toarray()
array([[1, 0, 3, 0],
[1, 2, 0, 4],
[0, 2, 3, 0],
[0, 0, 3, 4]])
```
```>>> from scipy.sparse import dia_matrix
>>> n = 10
>>> ex = np.ones(n)
>>> data = np.array([ex, 2 * ex, ex])
>>> offsets = np.array([-1, 0, 1])
>>> dia_matrix((data, offsets), shape=(n, n)).toarray()
array([[2., 1., 0., ..., 0., 0., 0.],
[1., 2., 1., ..., 0., 0., 0.],
[0., 1., 2., ..., 0., 0., 0.],
...,
[0., 0., 0., ..., 2., 1., 0.],
[0., 0., 0., ..., 1., 2., 1.],
[0., 0., 0., ..., 0., 1., 2.]])
```
Attributes
dtypedtype

Data type of the matrix

`shape`2-tuple

Get shape of a matrix.

ndimint

Number of dimensions (this is always 2)

`nnz`

Number of stored values, including explicit zeros.

data

DIA format data array of the matrix

offsets

DIA format offset array of the matrix

Methods

 `__mul__`(other) interpret other and call one of the following Element-wise arcsin. Element-wise arcsinh. Element-wise arctan. Element-wise arctanh. `asformat`(format[, copy]) Return this matrix in the passed format. Upcast matrix to a floating point format (if necessary) `astype`(dtype[, casting, copy]) Cast the matrix elements to a specified type. Element-wise ceil. `conj`([copy]) Element-wise complex conjugation. `conjugate`([copy]) Element-wise complex conjugation. Returns a copy of this matrix. Number of non-zero entries, equivalent to Element-wise deg2rad. `diagonal`([k]) Returns the kth diagonal of the matrix. `dot`(other) Ordinary dot product Element-wise expm1. Element-wise floor. Return the Hermitian transpose of this matrix. Get shape of a matrix. Returns a copy of column j of the matrix, as an (m x 1) sparse matrix (column vector). Format of a matrix representation as a string. Maximum number of elements to display when printed. `getnnz`([axis]) Number of stored values, including explicit zeros. Returns a copy of row i of the matrix, as a (1 x n) sparse matrix (row vector). Element-wise log1p. `maximum`(other) Element-wise maximum between this and another matrix. `mean`([axis, dtype, out]) Compute the arithmetic mean along the specified axis. `minimum`(other) Element-wise minimum between this and another matrix. `multiply`(other) Point-wise multiplication by another matrix nonzero indices `power`(n[, dtype]) This function performs element-wise power. Element-wise rad2deg. `reshape`(self, shape[, order, copy]) Gives a new shape to a sparse matrix without changing its data. `resize`(*shape) Resize the matrix in-place to dimensions given by `shape` Element-wise rint. `set_shape`(shape) `setdiag`(values[, k]) Set diagonal or off-diagonal elements of the array. Element-wise sign. Element-wise sin. Element-wise sinh. Element-wise sqrt. `sum`([axis, dtype, out]) Sum the matrix elements over a given axis. Element-wise tan. Element-wise tanh. `toarray`([order, out]) Return a dense ndarray representation of this matrix. `tobsr`([blocksize, copy]) Convert this matrix to Block Sparse Row format. `tocoo`([copy]) Convert this matrix to COOrdinate format. `tocsc`([copy]) Convert this matrix to Compressed Sparse Column format. `tocsr`([copy]) Convert this matrix to Compressed Sparse Row format. `todense`([order, out]) Return a dense matrix representation of this matrix. `todia`([copy]) Convert this matrix to sparse DIAgonal format. `todok`([copy]) Convert this matrix to Dictionary Of Keys format. `tolil`([copy]) Convert this matrix to List of Lists format. `transpose`([axes, copy]) Reverses the dimensions of the sparse matrix. Element-wise trunc.