Remove noexcept-s and simplify __copy__ and __deepcopy__

Author: gmou3

src/sage/matroids/flats_matroid.pxd

@@ -4,17 +4,17 @@ cdef class FlatsMatroid(Matroid):
     cdef frozenset _groundset  # _E
     cdef int _matroid_rank  # _R
     cdef dict _F  # flats
-    cpdef groundset(self) noexcept
-    cpdef _rank(self, X) noexcept
-    cpdef full_rank(self) noexcept
-    cpdef _is_independent(self, F) noexcept
+    cpdef groundset(self)
+    cpdef _rank(self, X)
+    cpdef full_rank(self)
+    cpdef _is_independent(self, F)
 
     # enumeration
-    cpdef flats(self, k) noexcept
-    cpdef whitney_numbers2(self) noexcept
+    cpdef flats(self, k)
+    cpdef whitney_numbers2(self)
 
     # isomorphism
-    cpdef _is_isomorphic(self, other, certificate=*) noexcept
+    cpdef _is_isomorphic(self, other, certificate=*)
 
     # verification
-    cpdef is_valid(self) noexcept
+    cpdef is_valid(self)

src/sage/matroids/flats_matroid.pyx

@@ -85,7 +85,7 @@ cdef class FlatsMatroid(Matroid):
                         self._F[i].add(frozenset(F))
         self._matroid_rank = max(self._F, default=-1)
 
-    cpdef groundset(self) noexcept:
+    cpdef groundset(self):
         """
         Return the groundset of the matroid.
 
@@ -102,7 +102,7 @@ cdef class FlatsMatroid(Matroid):
         """
         return self._groundset
 
-    cpdef _rank(self, X) noexcept:
+    cpdef _rank(self, X):
         """
         Return the rank of a set ``X``.
 
@@ -138,7 +138,7 @@ cdef class FlatsMatroid(Matroid):
 
     # optional
 
-    cpdef full_rank(self) noexcept:
+    cpdef full_rank(self):
         r"""
         Return the rank of the matroid.
 
@@ -156,7 +156,7 @@ cdef class FlatsMatroid(Matroid):
         """
         return self._matroid_rank
 
-    cpdef _is_isomorphic(self, other, certificate=False) noexcept:
+    cpdef _is_isomorphic(self, other, certificate=False):
         """
         Test if ``self`` is isomorphic to ``other``.
 
@@ -286,12 +286,7 @@ cdef class FlatsMatroid(Matroid):
             sage: M.groundset() is N.groundset()
             True
         """
-        N = FlatsMatroid(groundset=[], flats={})
-        N._groundset = self._groundset
-        N._F = self._F
-        N._matroid_rank = self._matroid_rank
-        N.rename(self.get_custom_name())
-        return N
+        return self
 
     def __deepcopy__(self, memo=None):
         """
@@ -309,15 +304,9 @@ cdef class FlatsMatroid(Matroid):
             sage: M == N
             True
             sage: M.groundset() is N.groundset()
-            False
+            True
         """
-        if memo is None:
-            memo = {}
-        from copy import deepcopy
-        # Since matroids are immutable, N cannot reference itself in correct code, so no need to worry about the recursion.
-        N = FlatsMatroid(groundset=deepcopy(self._groundset, memo), flats=deepcopy(self._F, memo))
-        N.rename(deepcopy(self.get_custom_name(), memo))
-        return N
+        return self
 
     def __reduce__(self):
         """
@@ -349,7 +338,7 @@ cdef class FlatsMatroid(Matroid):
 
     # enumeration
 
-    cpdef flats(self, k) noexcept:
+    cpdef flats(self, k):
         r"""
         Return the flats of the matroid of specified rank.
 
@@ -394,7 +383,7 @@ cdef class FlatsMatroid(Matroid):
             for F in self._F[k]:
                 yield F
 
-    cpdef whitney_numbers2(self) noexcept:
+    cpdef whitney_numbers2(self):
         r"""
         Return the Whitney numbers of the second kind of the matroid.
 
@@ -425,7 +414,7 @@ cdef class FlatsMatroid(Matroid):
 
     # verification
 
-    cpdef is_valid(self) noexcept:
+    cpdef is_valid(self):
         r"""
         Test if ``self`` obeys the matroid axioms.