Ticket #3676: 3676-ncalexan-docstring-changes.patch

sage/groups/perm_gps/partn_ref/refinement_graphs.pyx

@@ -22 +22 @@
     INPUT:
     G_in -- a Sage graph
     partition -- a list of lists representing a partition of the vertices
-    lab -- if True, return the canonical label in addition to the automorphism
-        group.
-    dig -- if True, does not use Lemma 2.25 in [1], and the algorithm is valid
-        for digraphs and graphs with loops.
-    dict_rep -- if True, explain which vertices are which elements of the set
-        {1,2,...,n} in the representation of the automorphism group.
-    certify -- if True, return the relabeling from G to its canonical
-        label.
+    lab -- if True, compute and return the canonical label in addition to the
+        automorphism group.
+    dig -- set to True for digraphs and graphs with loops.  If True, does not
+        use optimizations based on Lemma 2.25 in [1] that are valid only for
+        simple graphs.
+    dict_rep -- if True, return a dictionary with keys the vertices of the
+        input graph G_in and values elements of the set the permutation group
+        acts on.  (The point is that graphs are arbitrarily labelled, often
+        0..n-1, and permutation groups always act on 1..n.  This dictionary
+        maps vertex labels (such as 0..n-1) to the domain of the permutations.)
+    certify -- if True, return the permutation from G to its canonical label.
     verbosity -- currently ignored
     use_indicator_function -- option to turn off indicator function
-        (False -> slower)
+        (True is generally faster)
     sparse -- whether to use sparse or dense representation of the graph
         (ignored if G is already a CGraph - see sage.graphs.base)
     base -- whether to return the first sequence of split vertices (used in
@@ -314 +317 @@
         return tuple(return_tuple)
 
 cdef int refine_by_degree(PartitionStack *PS, object S, int *cells_to_refine_by, int ctrb_len):
-    """
+    r"""
     Refines the input partition by checking degrees of vertices to the given
     cells.
     
@@ -325 +328 @@
         question, and some flags.
     cells_to_refine_by -- a list of pointers to cells to check degrees against
         in refining the other cells (updated in place)
-    ctrb_len -- how many cells in the above
+    ctrb_len -- how many cells in cells_to_refine_by
     
     OUTPUT:
-    An invariant, such that if the function is called with a permutation of the
-    situation (i.e. there is a gamma taking one graph to the other, which also
-    takes one partition to the other), the same number is returned.
+
+    An integer invariant under the orbits of $S_n$.  That is, if $\gamma$ is a
+    permutation of the vertices, then
+    $$ I(G, PS, cells_to_refine_by) = I( \gamma(G), \gamma(PS), \gamma(cells_to_refine_by) ) .$$
+
     """
     cdef GraphStruct GS = <GraphStruct> S
     cdef CGraph G = GS.G
@@ -425 +430 @@
         return 0
     
 cdef int compare_graphs(int *gamma_1, int *gamma_2, object S):
-    """
-    Compare gamma_1(G) and gamma_2(G), returning 0 iff gamma_1(G) == gamma_2(G).
+    r"""
+    Compare gamma_1(G) and gamma_2(G).
+
+    Return return -1 if gamma_1(G) < gamma_2(G), 0 if gamma_1(G) ==
+    gamma_2(G), 1 if gamma_1(G) > gamma_2(G).  (Just like the python
+    \code{cmp}) function.
     
     INPUT:
     gamma_1, gamma_2 -- list permutations (inverse)
@@ -447 +456 @@
 
 cdef bint all_children_are_equivalent(PartitionStack *PS, object S):
     """
-    Returns True if any refinement of the current partition results in the same
-    structure. Converse does not hold in general.
-    
+    Return True if every refinement of the current partition results in the
+    same structure.
+
+    WARNING:
+    Converse does not hold in general!  See Lemma 2.25 of [1] for details.
+
     INPUT:
     PS -- the partition stack to be checked
     S -- a graph struct object
@@ -606 +618 @@
     """
     Tests to make sure that C(gamma(G)) == C(G) for random permutations gamma
     and random graphs G.
-    
-    DOCTEST:
+
+    INPUT:
+    t -- run tests for approximately this many seconds
+    n_max -- test graphs with at most this many vertices
+    perms_per_graph -- test each graph with this many random permutations
+
+    DISCUSSION:
+
+    Until t seconds have elapsed, this code generates a random graph G on at
+    most n_max vertices.  The density of edges is chosen randomly between 0
+    and 1.
+
+    For each graph G generated, we uniformly generate perms_per_graph random
+    permutations and verify that the canonical labels of G and the image of G
+    under the generated permutation are equal.
+        
+    TESTS:
         sage: import sage.groups.perm_gps.partn_ref.refinement_graphs
         sage: sage.groups.perm_gps.partn_ref.refinement_graphs.random_tests()
         All passed: ... random tests on ... graphs.