immutablematrices.rst

Immutable Matrices

The standard Matrix class in Diofant is mutable. This is important for performance reasons but means that standard matrices cannot interact well with the rest of Diofant. This is because the :class:`~diofant.core.basic.Basic` object, from which most Diofant classes inherit, is immutable.

The mission of the :class:`~diofant.matrices.immutable.ImmutableMatrix` class is to bridge the tension between performance/mutability and safety/immutability. Immutable matrices can do almost everything that normal matrices can do but they inherit from :class:`~diofant.core.basic.Basic` and can thus interact more naturally with the rest of Diofant. :class:`~diofant.matrices.immutable.ImmutableMatrix` also inherits from :class:`~diofant.matrices.expressions.MatrixExpr`, allowing it to interact freely with Diofant's Matrix Expression module.

You can turn any Matrix-like object into an :class:`~diofant.matrices.immutable.ImmutableMatrix` by calling the constructor

>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> M[1, 1] = 0
>>> IM = ImmutableMatrix(M)
>>> IM
Matrix([
[1, 2, 3],
[4, 0, 6],
[7, 8, 9]])
>>> IM[1, 1] = 5
Traceback (most recent call last):
...
TypeError: Can not set values in Immutable Matrix. Use Matrix instead.

ImmutableMatrix Class Reference

.. module:: diofant.matrices.immutable

.. autoclass:: ImmutableMatrix
   :members: