konieczny: add init mem fn

src/konieczny.cpp

@@ -101,6 +101,20 @@ occur in *gens*.
   if the items in *gens* do not all have the same degree.
 )pbdoc");
 
+      thing.def("init",
+                &Konieczny_::init,
+                R"pbdoc(
+:sig=(self: Konieczny) -> Konieczny:
+
+Reinitialize an existing :any:`Konieczny` object.
+
+This function re-initializes a :any:`Konieczny` instance so that it is in the
+same (logical) state as if it had just been default-constructed.
+
+:returns: ``self``.
+:rtype: Konieczny
+)pbdoc");
+
       // This constructor can't be used directly so isn't documented.
       thing.def(py::init<>(), R"pbdoc(
 :sig=(self: Konieczny, gens: list[Element]) -> None:
@@ -726,7 +740,7 @@ not already known.
    int
 )pbdoc");
     }  // bind_konieczny
-  }    // namespace
+  }  // namespace
 
   void init_konieczny(py::module& m) {
     bind_konieczny<BMat8>(m, "BMat8");

tests/test_konieczny.py

@@ -47,7 +47,10 @@ def test_case_031():
     )
     assert k.size() == 3125
 
-    val = sum(k.D_class_of_element(x.rep()).number_of_idempotents() for x in k.D_classes())
+    val = sum(
+        k.D_class_of_element(x.rep()).number_of_idempotents()
+        for x in k.D_classes()
+    )
     assert val == 196
     assert k.number_of_idempotents() == 196
     assert list(k.generators()) == [
@@ -73,7 +76,10 @@ def test_case_032():
         ]
     )
     assert S.size() == 597369
-    val = sum(S.D_class_of_element(x.rep()).number_of_idempotents() for x in S.D_classes())
+    val = sum(
+        S.D_class_of_element(x.rep()).number_of_idempotents()
+        for x in S.D_classes()
+    )
     assert val == 8194
     assert S.number_of_idempotents() == 8194
 
@@ -279,7 +285,9 @@ def test_case_040():
     S.run_until(lambda: S.current_number_of_regular_D_classes() > 2)
 
     assert S.current_number_of_regular_D_classes() < 5
-    assert S.current_number_of_D_classes() - S.number_of_regular_D_classes() < 2117
+    assert (
+        S.current_number_of_D_classes() - S.number_of_regular_D_classes() < 2117
+    )
 
 
 def test_case_041():
@@ -299,7 +307,10 @@ def test_case_041():
     S.run_until(lambda: S.current_number_of_regular_D_classes() > 2)
     S.run()
     assert S.current_number_of_regular_D_classes() == 5
-    assert S.current_number_of_D_classes() - S.number_of_regular_D_classes() == 2117
+    assert (
+        S.current_number_of_D_classes() - S.number_of_regular_D_classes()
+        == 2117
+    )
 
 
 def check_case_000(Mat):
@@ -403,7 +414,9 @@ def test_case_028():
         assert x in S
         assert x in S.D_class_of_element(x)
     assert PPerm([0, 1, 2, 3, 4, 5, 6, 7], [1, 7, 2, 6, 0, 4, 8, 5], 9) not in S
-    assert not S.contains(PPerm([0, 1, 2, 3, 4, 5, 6, 7], [0, 1, 2, 3, 4, 5, 6, 8], 9))
+    assert not S.contains(
+        PPerm([0, 1, 2, 3, 4, 5, 6, 7], [0, 1, 2, 3, 4, 5, 6, 8], 9)
+    )
     assert S.contains(PPerm([], [], 9))
     assert S.size() == 21033
     assert S.number_of_D_classes() == 3242
@@ -425,6 +438,27 @@ def test_case_029():
     assert S.number_of_D_classes() == 9
 
 
+def test_konieczny_init():
+    "symmetric inverse monoid n = 7"
+    ReportGuard(False)
+    S = Konieczny(
+        [
+            PPerm([0, 1, 2, 3, 4, 5, 6, 7], [0, 1, 2, 3, 4, 5, 6, 7], 8),
+            PPerm([0, 1, 2, 3, 4, 5, 6, 7], [1, 2, 3, 4, 5, 6, 7, 0], 8),
+            PPerm([0, 1, 2, 3, 4, 5, 6, 7], [1, 0, 2, 3, 4, 5, 6, 7], 8),
+            PPerm([0, 1, 2, 3, 4, 5, 6], [1, 2, 3, 4, 5, 6, 7], 8),
+        ]
+    )
+    assert S.size() == 1441729
+    assert S.number_of_D_classes() == 9
+    S.init()
+    assert S.number_of_generators() == 0
+    S.add_generator(
+        PPerm([0, 1, 2, 3, 4, 5, 6, 7], [0, 1, 2, 3, 4, 5, 6, 7], 8)
+    )
+    assert S.size() == 1
+
+
 def test_case_030():
     "exceptions"
     ReportGuard(False)
@@ -460,4 +494,7 @@ def test_konieczny_return_policy():
     assert S.add_generators(gens) is S
     assert S.D_class_of_element(gens[0]) is S.D_class_of_element(gens[0])
     assert S.generator(0) is S.generator(0)
-    assert S.D_class_of_element(gens[0]).rep() is S.D_class_of_element(gens[0]).rep()
+    assert (
+        S.D_class_of_element(gens[0]).rep()
+        is S.D_class_of_element(gens[0]).rep()
+    )