Opened 9 years ago

Closed 9 years ago

#13238 closed enhancement (fixed)

add functionality for counting, generating, and manipulating non-negative integer matrices

Reported by: saliola Owned by: sage-combinat
Priority: major Milestone: sage-5.3
Component: combinatorics Keywords: sd40, ncsf
Cc: chrisjamesberg Merged in: sage-5.3.beta0
Authors: Franco Saliola Reviewers: Chris Berg
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description

Counting, generating, and manipulating non-negative integer matrices with prescribed row sums and column sums.

    An *integer matrix* `m` with column sums `c := (c_1,...,c_k)` and row
    sums `l := (l_1,...,l_n)` where `c_1+...+c_k` is equal to `l_1+...+l_n`,
    is a `n \times k` matrix `m = (m_{i,j})` such that
    `m_{1,j}+\dots+m_{n,j} = c_j`, for all `j` and
    `m_{i,1}+\dots+m_{i,k} = l_i`, for all `i`.

    EXAMPLES:

    There are `6` integer matrices with row sums `[3,2,2]` and column sums
    `[2,5]`::

        sage: from sage.combinat.integer_matrices import IntegerMatrices
        sage: IM = IntegerMatrices([3,2,2], [2,5]); IM
        Non-negative integer matrices with row sums [3, 2, 2] and column sums [2, 5]
        sage: IM.list()
        [
        [2 1]  [1 2]  [1 2]  [0 3]  [0 3]  [0 3]
        [0 2]  [1 1]  [0 2]  [2 0]  [1 1]  [0 2]
        [0 2], [0 2], [1 1], [0 2], [1 1], [2 0]
        ]
        sage: IM.cardinality()
        6

Attachments (1)

trac_13238-integer_matrices-fs.patch (12.1 KB) - added by saliola 9 years ago.

Download all attachments as: .zip

Change History (5)

comment:1 Changed 9 years ago by saliola

  • Summary changed from Counting, generating, and manipulating non-negative integer matrices to add functionality for counting, generating, and manipulating non-negative integer matrices

comment:2 Changed 9 years ago by saliola

  • Status changed from new to needs_review

Changed 9 years ago by saliola

comment:3 Changed 9 years ago by chrisjamesberg

  • Status changed from needs_review to positive_review

comment:4 Changed 9 years ago by jdemeyer

  • Merged in set to sage-5.3.beta0
  • Resolution set to fixed
  • Status changed from positive_review to closed
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