From b106a4421f9dbdaabebe44c3d689c08b939229f1 Mon Sep 17 00:00:00 2001
From: James Mitchell <jdm3@st-andrews.ac.uk>
Date: Wed, 22 Jun 2016 17:36:20 +0100
Subject: [PATCH] Fix bug in FixedPoints for a partial perm coll

Previously it called MovedPoints!
---
 lib/pperm.gi                  |  2 +-
 lib/semipperm.gi              |  2 +-
 tst/testinstall/semipperm.tst | 41 +++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 tst/testinstall/semipperm.tst

diff --git a/lib/pperm.gi b/lib/pperm.gi
index 25eeda2e8a..d9ce3970ba 100644
--- a/lib/pperm.gi
+++ b/lib/pperm.gi
@@ -740,7 +740,7 @@ InstallMethod(MovedPoints, "for a partial perm coll",
 [IsPartialPermCollection], coll-> Union(List(coll, MovedPoints)));
 
 InstallMethod(NrFixedPoints, "for a partial perm coll",
-[IsPartialPermCollection], coll-> Length(MovedPoints(coll)));
+[IsPartialPermCollection], coll-> Length(FixedPointsOfPartialPerm(coll)));
 
 InstallMethod(NrMovedPoints, "for a partial perm coll",
 [IsPartialPermCollection], coll-> Length(MovedPoints(coll)));
diff --git a/lib/semipperm.gi b/lib/semipperm.gi
index e5ae6c57f3..24af84a0b9 100644
--- a/lib/semipperm.gi
+++ b/lib/semipperm.gi
@@ -109,7 +109,7 @@ s-> ImageOfPartialPermCollection(GeneratorsOfSemigroup(s)));
 
 InstallMethod(FixedPointsOfPartialPerm, "for a partial perm semigroup",
 [IsPartialPermSemigroup],
-s-> MovedPoints(GeneratorsOfSemigroup(s)));
+s-> FixedPointsOfPartialPerm(GeneratorsOfSemigroup(s)));
 
 InstallMethod(MovedPoints, "for a partial perm semigroup",
 [IsPartialPermSemigroup],
diff --git a/tst/testinstall/semipperm.tst b/tst/testinstall/semipperm.tst
new file mode 100644
index 0000000000..332275e5ee
--- /dev/null
+++ b/tst/testinstall/semipperm.tst
@@ -0,0 +1,41 @@
+#############################################################################
+##
+#W  semipperm.tst
+#Y  James D. Mitchell
+##
+#############################################################################
+##
+gap> START_TEST("semipperm.tst");
+
+# Test DisplayString
+gap> S := Semigroup(PartialPerm([1, 2, 3], [4, 5, 11]), 
+>                   PartialPerm([1], [3]));;
+gap> DisplayString(S);
+"\><\>partial perm\< \>semigroup\< \>of\< \>rank \>3\<\< \>with\< \>2\< \>gene\
+rators\<>\<"
+
+# Test Fixed/moved points etc
+gap> S := Semigroup(PartialPerm([1, 2, 3, 4, 6, 7, 10], [10, 8, 4, 6, 5, 3, 2]),
+>              PartialPerm([1, 2, 4, 5, 6, 9, 10], [3, 5, 8, 4, 1, 9, 7]),
+>              PartialPerm([1, 2, 4, 7, 9], [5, 3, 7, 4, 9]),
+>              PartialPerm([1, 2, 3, 4, 6, 8], [5, 1, 10, 7, 8, 9]));
+<partial perm semigroup of rank 10 with 4 generators>
+gap> FixedPointsOfPartialPerm(S);
+[ 9 ]
+gap> MovedPoints(S);
+[ 1, 2, 3, 4, 5, 6, 7, 8, 10 ]
+gap> NrFixedPoints(S);
+1
+gap> NrMovedPoints(S);
+9
+gap> LargestMovedPoint(S);
+10
+gap> LargestImageOfMovedPoint(S);
+10
+gap> SmallestMovedPoint(S);
+1
+gap> SmallestImageOfMovedPoint(S);
+1
+
+#
+gap> STOP_TEST( "semipperm.tst", 10000);