Cleanup of integer compositions

[nthiery]

• Documentation improvements
• Fixes some of http://wiki.sagemath.org/combinat/Weirdness
• Composition(l) accepts any iterable l, and in particular a tuple
• New functionalities:
  • concatenation (as __add__ and sum)
  • size
  • fatter, finer, fatten (refinement of compositions)
• Uses IntegerListsLex (fast iteration, ...) instead of not any better specific code
  Note: this changes the iteration order to inverse lexicographic,
  and iteration changes the iteration order for set partitions, skew
  partitions, and skew tableaux.

CC: @sagetrac-sage-combinat @jbandlow

Component: combinatorics

Keywords: integer compositions

Author: Nicolas M. Thiéry

Reviewer: Dan Drake, Jason Bandlow, Minh Van Nguyen

Merged: Sage 4.1.2.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/5600

[nthiery]

Description changed:

--- 
+++ 
@@ -1,5 +1,5 @@
 Fix  some weirdness of http://wiki.sagemath.org/combinat/Weirdness:
-See compositions-cleanup-....-nt.patch
+See compositions-cleanup-5600-nt.patch
 
 Accept any iterable as input
 Adds concatenation of compositions

[nthiery]

Description changed:

--- 
+++ 
@@ -1,5 +1,6 @@
-Fix  some weirdness of http://wiki.sagemath.org/combinat/Weirdness:
-See compositions-cleanup-5600-nt.patch
+See http://wiki.sagemath.org/combinat/Weirdness:
+See compositions-cleanup-5600-nt.patch on the sage-combinat patch server
 
-Accept any iterable as input
-Adds concatenation of compositions
+* Documentation improvements
+* Accept any iterable as input
+* Adds concatenation of compositions

[nthiery]

Description changed:

--- 
+++ 
@@ -4,3 +4,4 @@
 * Documentation improvements
 * Accept any iterable as input
 * Adds concatenation of compositions
+* Use IntegerListLex (fast generation!)

[nthiery]

Description changed:

--- 
+++ 
@@ -1,7 +1,11 @@
-See http://wiki.sagemath.org/combinat/Weirdness:
-See compositions-cleanup-5600-nt.patch on the sage-combinat patch server
-
-* Documentation improvements
-* Accept any iterable as input
-* Adds concatenation of compositions
-* Use IntegerListLex (fast generation!)
+- Documentation improvements
+- Fixes some of http://wiki.sagemath.org/combinat/Weirdness
+- Composition(l) accepts any iterable l, and in particular a tuple
+- New functionalities:
+   - concatenation (as `__add__` and sum)
+   - size
+   - fatter, finer, fatten (refinement of compositions)
+- Uses IntegerListsLex (fast iteration, ...) instead of not any better specific code
+  Note: this changes the iteration order to inverse lexicographic,
+  and iteration changes the iteration order for set partitions, skew
+  partitions, and skew tableaux.

[nthiery]

Changed keywords from none to integer compositions

[nthiery]

comment:6

Attachment: compositions-cleanup-5600-nt.patch.gz

[dandrake]

comment:7

I very much want this patch to get in, since I almost opened a ticket for one of the problems that it fixes. (Composition() doesn't take tuples as input.) One thing that needs to change, though, is with the docstring for Composition: right now, it tells the user to do Composition_class?, but that doesn't work since Composition_class is not in the default namespace. I think Composition? should simply display the correct docstring; there's no need to annoy the user by sending him or her bouncing from one docstring to the next.

Another issue is that the AUTHORS block is deleted from the head of the file. This should not be done. In fact, you should add yourself to it as the developer's guide suggests: something like "Nicolas M. Thiery (2009-05-25): several cleanups, new functions, and improvements (trac #5600)". I like listing ticket numbers because interested developers can go see exactly what you changed.

Tiny grammar/spelling issues:

• At the top of compositions.py, you write "a compositions c of..."; you should use the singular. "A composition c of..."
• line 56: you say a composition is a list of positive integers, but it should be a list of nonnegative integers.

Finally, I am seeing a doctest failure with this patch applied to vanilla 4.0.rc0:

**********************************************************************
File "/var/tmp/sage-4.0.rc0/devel/sage/sage/combinat/ribbon_tableau.py", line 875:
    sage: SemistandardMultiSkewTableaux([sp[0], sp[-1]],[2,2,2]).list()
Expected:
    [[[[1], [2], [3]], [[1, 2, 3]]]]
Got:
    [[[[1, 1, 2]], [[None, None, 3], [None, 3], [2]]], [[[1, 2, 2]], [[None, None, 3], [None, 3], [1]]], [[[1, 1, 2]], [[None, None, 3], [None, 2], [3]]], [[[1, 2, 2]], [[None, None, 3], [None, 1], [3]]], [[[1, 1, 2]], [[None, None, 2], [None, 3], [3]]], [[[1, 2, 2]], [[None, None, 1], [None, 3], [3]]], [[[1, 1, 3]], [[None, None, 3], [None, 2], [2]]], [[[1, 2, 3]], [[None, None, 3], [None, 2], [1]]], [[[1, 2, 3]], [[None, None, 3], [None, 1], [2]]], [[[2, 2, 3]], [[None, None, 3], [None, 1], [1]]], [[[1, 1, 3]], [[None, None, 2], [None, 3], [2]]], [[[1, 2, 3]], [[None, None, 2], [None, 3], [1]]], [[[1, 2, 3]], [[None, None, 1], [None, 3], [2]]], [[[2, 2, 3]], [[None, None, 1], [None, 3], [1]]], [[[1, 1, 3]], [[None, None, 2], [None, 2], [3]]], [[[1, 2, 3]], [[None, None, 2], [None, 1], [3]]], [[[1, 2, 3]], [[None, None, 1], [None, 2], [3]]], [[[2, 2, 3]], [[None, None, 1], [None, 1], [3]]], [[[1, 3, 3]], [[None, None, 2], [None, 2], [1]]], [[[1, 3, 3]], [[None, None, 2], [None, 1], [2]]], [[[1, 3, 3]], [[None, None, 1], [None, 2], [2]]], [[[2, 3, 3]], [[None, None, 2], [None, 1], [1]]], [[[2, 3, 3]], [[None, None, 1], [None, 2], [1]]], [[[2, 3, 3]], [[None, None, 1], [None, 1], [2]]]]
**********************************************************************