AUTHORS:
Return an iterator over the list of integer vectors which are componentwise less than or equal to vect, and lexicographically greater than or equal to min.
INPUT:
OUTPUT:
A list in lexicograohic order of all integer vectors (as lists) which are dominated elementwise by vect and are greater than or equal to min in lexicographic order.
EXAMPLES:
sage: from sage.combinat.vector_partition import IntegerVectorsIterator
sage: list(IntegerVectorsIterator([1, 1]))
[[0, 0], [0, 1], [1, 0], [1, 1]]
sage: list(IntegerVectorsIterator([1, 1], min = [1, 0]))
[[1, 0], [1, 1]]
Bases: sage.combinat.combinat.CombinatorialObject, sage.structure.element.Element
A vector partition is a multiset of integer vectors.
Return the partition obtained by sorting the i-th elements of the vectors in the vector partition.
EXAMPLES:
sage: V = VectorPartition([[1, 2, 1], [2, 4, 1]])
sage: V.partition_at_vertex(1)
[4, 2]
Return the sum vector as a list.
EXAMPLES:
sage: V = VectorPartition([[3, 2, 1], [2, 2, 1]])
sage: V.sum()
[5, 4, 2]
Bases: sage.structure.parent.Parent, sage.structure.unique_representation.UniqueRepresentation
Class of all vector partitions of vec with all parts greater than or equal to min in lexicographic order.
A vector partition of vec is a list of vectors with non-negative integer entries whose sum is vec.
INPUT:
EXAMPLES:
If min is not specified, then the class of all vector partitions of vec is created:
sage: VP = VectorPartitions([2, 2])
sage: for vecpar in VP:
....: print vecpar
[[0, 1], [0, 1], [1, 0], [1, 0]]
[[0, 1], [0, 1], [2, 0]]
[[0, 1], [1, 0], [1, 1]]
[[0, 1], [2, 1]]
[[0, 2], [1, 0], [1, 0]]
[[0, 2], [2, 0]]
[[1, 0], [1, 2]]
[[1, 1], [1, 1]]
[[2, 2]]
If min is specified, then the class consists of only those vector partitions whose parts are all greater than or equal to min in lexicographic order:
sage: VP = VectorPartitions([2, 2], min = [1, 0])
sage: for vecpar in VP:
....: print vecpar
[[1, 0], [1, 2]]
[[1, 1], [1, 1]]
[[2, 2]]
alias of VectorPartition
Return a string of 0‘s with one 1 at the location where the list vect has its last entry which is not equal to 0.
INPUT:
OUTPUT:
A list of the same length with 0‘s everywhere, except for a 1 at the last position where vec has an entry not equal to 0.
EXAMPLES:
sage: from sage.combinat.vector_partition import find_min
sage: find_min([2, 1])
[0, 1]
sage: find_min([2, 1, 0])
[0, 1, 0]