Merge sagemath#32888

Author: mkoeppe

src/sage/features/sagemath.py

@@ -74,6 +74,28 @@ def __init__(self):
                              [PythonModule('sage.graphs.graph')])
 
 
+class sage__groups(JoinFeature):
+    r"""
+    A :class:`sage.features.Feature` describing the presence of ``sage.groups``.
+
+    EXAMPLES::
+
+        sage: from sage.features.sagemath import sage__groups
+        sage: sage__groups().is_present()  # optional - sage.groups
+        FeatureTestResult('sage.groups', True)
+    """
+    def __init__(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features.sagemath import sage__groups
+            sage: isinstance(sage__groups(), sage__groups)
+            True
+        """
+        JoinFeature.__init__(self, 'sage.groups',
+                             [PythonModule('sage.groups.perm_gps.permgroup')])
+
+
 class sage__plot(JoinFeature):
     r"""
     A :class:`sage.features.Feature` describing the presence of ``sage.plot``.
@@ -186,6 +208,7 @@ def all_features():
     return [sage__combinat(),
             sage__geometry__polyhedron(),
             sage__graphs(),
+            sage__groups(),
             sage__plot(),
             sage__rings__number_field(),
             sage__rings__real_double(),

src/sage/structure/coerce.pyx

@@ -1085,8 +1085,8 @@ cdef class CoercionModel:
             sage: Zmod100 = Integers(100)
             sage: cm.division_parent(Zmod100)
             Ring of integers modulo 100
-            sage: S5 = SymmetricGroup(5)
-            sage: cm.division_parent(S5)
+            sage: S5 = SymmetricGroup(5)                                                # optional - sage.groups
+            sage: cm.division_parent(S5)                                                # optional - sage.groups
             Symmetric group of order 5! as a permutation group
         """
         try:

src/sage/structure/coerce_actions.pyx

@@ -97,10 +97,10 @@ cdef class GenericAction(Action):
             sage: A.codomain()
             Set P^1(QQ) of all cusps
 
-            sage: S3 = SymmetricGroup(3)
-            sage: QQxyz = QQ['x,y,z']
-            sage: A = sage.structure.coerce_actions.ActOnAction(S3, QQxyz, False)
-            sage: A.codomain()
+            sage: S3 = SymmetricGroup(3)                                                # optional - sage.groups
+            sage: QQxyz = QQ['x,y,z']                                                   # optional - sage.groups
+            sage: A = sage.structure.coerce_actions.ActOnAction(S3, QQxyz, False)       # optional - sage.groups
+            sage: A.codomain()                                                          # optional - sage.groups
             Multivariate Polynomial Ring in x, y, z over Rational Field
 
         """
@@ -118,15 +118,15 @@ cdef class ActOnAction(GenericAction):
         """
         TESTS::
 
-            sage: G = SymmetricGroup(3)
-            sage: R.<x,y,z> = QQ[]
-            sage: A = sage.structure.coerce_actions.ActOnAction(G, R, False)
-            sage: A(x^2 + y - z, G((1,2)))
+            sage: G = SymmetricGroup(3)                                                 # optional - sage.groups
+            sage: R.<x,y,z> = QQ[]                                                      # optional - sage.groups
+            sage: A = sage.structure.coerce_actions.ActOnAction(G, R, False)            # optional - sage.groups
+            sage: A(x^2 + y - z, G((1,2)))                                              # optional - sage.groups
             y^2 + x - z
-            sage: A(x+2*y+3*z, G((1,3,2)))
+            sage: A(x+2*y+3*z, G((1,3,2)))                                              # optional - sage.groups
             2*x + 3*y + z
 
-            sage: type(A)
+            sage: type(A)                                                               # optional - sage.groups
             <... 'sage.structure.coerce_actions.ActOnAction'>
         """
         return (<Element>g)._act_on_(x, self._is_left)

src/sage/structure/element.pyx

@@ -2549,9 +2549,9 @@ cdef class MonoidElement(Element):
 
         EXAMPLES::
 
-            sage: G = SymmetricGroup(4)
-            sage: g = G([2, 3, 4, 1])
-            sage: g.powers(4)
+            sage: G = SymmetricGroup(4)                                 # optional - sage.groups
+            sage: g = G([2, 3, 4, 1])                                   # optional - sage.groups
+            sage: g.powers(4)                                           # optional - sage.groups
             [(), (1,2,3,4), (1,3)(2,4), (1,4,3,2)]
         """
         if n < 0: