Matrix Normal Forms

Matrix Normal Forms

sympy.matrices.normalforms.smith_normal_form(m, domain=None)[source]

Return the Smith Normal Form of a matrix \(m\) over the ring \(domain\). This will only work if the ring is a principal ideal domain.

Examples

>>> from sympy import Matrix, ZZ
>>> from sympy.matrices.normalforms import smith_normal_form
>>> m = Matrix([[12, 6, 4], [3, 9, 6], [2, 16, 14]])
>>> print(smith_normal_form(m, domain=ZZ))
Matrix([[1, 0, 0], [0, 10, 0], [0, 0, -30]])
sympy.matrices.normalforms.hermite_normal_form(A, *, D=None, check_rank=False)[source]

Compute the Hermite Normal Form of a Matrix A of integers.

Parameters

A : \(m \times n\) Matrix of integers.

D : int, optional

Let \(W\) be the HNF of A. If known in advance, a positive integer D being any multiple of \(\det(W)\) may be provided. In this case, if A also has rank \(m\), then we may use an alternative algorithm that works mod D in order to prevent coefficient explosion.

check_rank : boolean, optional (default=False)

The basic assumption is that, if you pass a value for D, then you already believe that A has rank \(m\), so we do not waste time checking it for you. If you do want this to be checked (and the ordinary, non-modulo D algorithm to be used if the check fails), then set check_rank to True.

Returns

Matrix

The HNF of matrix A.

Raises

DMDomainError

If the domain of the matrix is not ZZ.

DMShapeError

If the mod D algorithm is used but the matrix has more rows than columns.

Examples

>>> from sympy import Matrix
>>> from sympy.matrices.normalforms import hermite_normal_form
>>> m = Matrix([[12, 6, 4], [3, 9, 6], [2, 16, 14]])
>>> print(hermite_normal_form(m))
Matrix([[10, 0, 2], [0, 15, 3], [0, 0, 2]])

References

R593

Cohen, H. A Course in Computational Algebraic Number Theory. (See Algorithms 2.4.5 and 2.4.8.)

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