Arbitrary precision complex ball matrices using Arb¶

AUTHORS:

Clemens Heuberger (2014-10-25): Initial version.

This is a rudimentary binding to the Arb library; it may be useful to refer to its documentation for more details.

class sage.matrix.matrix_complex_ball_dense.Matrix_complex_ball_dense¶

Bases: sage.matrix.matrix_dense.Matrix_dense

Matrix over a complex ball field. Implemented using the acb_mat type of the Arb library.

EXAMPLES:

sage: MatrixSpace(CBF, 3)(2)
[2.000000000000000                 0                 0]
[                0 2.000000000000000                 0]
[                0                 0 2.000000000000000]
sage: matrix(CBF, 1, 3, [1, 2, -3])
[ 1.000000000000000  2.000000000000000 -3.000000000000000]

charpoly(var='x', algorithm=None)¶

Compute the characteristic polynomial of this matrix.

EXAMPLES:

sage: from sage.matrix.benchmark import hilbert_matrix
sage: mat = hilbert_matrix(5).change_ring(ComplexBallField(10))
sage: mat.charpoly()
x^5 + ([-1.8 +/- 0.0258])*x^4 + ([0.3 +/- 0.05...)*x^3 +
([+/- 0.0...])*x^2 + ([+/- 0.0...])*x + [+/- 0.0...]

contains(other)¶

Test if the set of complex matrices represented by self is contained in that represented by other.

EXAMPLES:

sage: b = CBF(0, RBF(0, rad=.1r)); b
[+/- 0.101]*I
sage: matrix(CBF, [0, b]).contains(matrix(CBF, [0, 0]))
True
sage: matrix(CBF, [0, b]).contains(matrix(CBF, [b, 0]))
False
sage: matrix(CBF, [b, b]).contains(matrix(CBF, [b, 0]))
True

determinant()¶

Compute the determinant of this matrix.

EXAMPLES:

sage: matrix(CBF, [[1/2, 1/3], [1, 1]]).determinant()
[0.1666666666666667 +/- ...e-17]
sage: matrix(CBF, [[1/2, 1/3], [1, 1]]).det()
[0.1666666666666667 +/- ...e-17]
sage: matrix(CBF, [[1/2, 1/3]]).determinant()
Traceback (most recent call last):
...
ValueError: self must be a square matrix

eigenvalues(other=None, extend=None)¶

(Experimental.) Compute rigorous enclosures of the eigenvalues of this matrix.

INPUT:

self – an \(n \times n\) matrix
other – unsupported (generalized eigenvalue problem), should be None
extend – ignored

OUTPUT:

A Sequence of complex balls of length equal to the size of the matrix.

Each element represents one eigenvalue with the correct multiplicities in case of overlap. The output intervals are either disjoint or identical, and identical intervals are guaranteed to be grouped consecutively. Each complete run of \(k\) identical balls thus represents a cluster of exactly \(k\) eigenvalues which could not be separated from each other at the current precision, but which could be isolated from the other eigenvalues.

There is currently no guarantee that the algorithm converges as the working precision is increased.

See the Arb documentation for more information.

EXAMPLES:

sage: from sage.matrix.benchmark import hilbert_matrix
sage: mat = hilbert_matrix(5).change_ring(CBF)
sage: mat.eigenvalues()
doctest:...: FutureWarning: This class/method/function is marked as experimental.
...
[[1.567050691098...] + [+/- ...]*I, [0.208534218611...] + [+/- ...]*I,
[3.287928...e-6...] + [+/- ...]*I, [0.000305898040...] + [+/- ...]*I,
[0.011407491623...] + [+/- ...]*I]

sage: mat = Permutation([2, 1, 4, 5, 3]).to_matrix().dense_matrix().change_ring(CBF)
sage: mat.eigenvalues()
Traceback (most recent call last):
...
ValueError: unable to certify the eigenvalues
sage: precond = matrix(ZZ, [[-1, -2, 2, 2, -2], [2, -2, -2, -2, 2],
....:     [-2, 2, -1, 2, 1], [2, 1, -1, 0, 2], [-2, 0, 1, -1, 1]])
sage: (~precond*mat*precond).eigenvalues()
[[-0.5000000000000...] + [-0.8660254037844...]*I, [-1.000000000000...] + [+/- ...]*I,
 [-0.5000000000000...] + [0.8660254037844...]*I,
 [1.000000000000...] + [+/- ...]*I, [1.000000000000...] + [+/- ...]*I]

Arbitrary precision complex ball matrices using Arb¶

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