Add 'largest_required_point'

gap/BacktrackKit.gi

@@ -129,6 +129,10 @@ end;
 InitialiseConstraints := function(state, tracer, rbase)
     local c, filters;
     for c in state!.conlist do
+        if c!.largest_required_point > PS_Points(state!.ps) then
+            ErrorNoReturn(StringFormatted("Refiner {} requires {} points, but the partition only has {}",
+                           c!.name, c!.largest_required_point, PS_Points(state!.ps)));
+        fi;
         if IsBound(c!.refine.initialise) then
             filters := c!.refine.initialise(state!.ps, rbase);
             if not ApplyFilters(state, tracer, filters) then

gap/constraint.gd

@@ -13,6 +13,14 @@
 #!
 #! * A member called <C>name</C>, which is a string giving the name of the
 #!   constraint;
+#! * A member called <C>largest_required_point</C>, which is an integer
+#!   which gives the smallest size partition this refiner will work on.
+#!   For example, given a set we would expect this to be the largest element
+#!   of the set.
+#! * An optional member called <C>largest_moved_point</C>, which is an integer
+#!   giving an upper bound on the largest point this refiner could ever move.
+#!   For many refiners this will not exist -- for example a 'set stabilizer'
+#!   refiner will always permute values outside the set.
 #! * A member called <C>refine</C>, which is a record; more information is
 #!   given below.
 #!

gap/constraints/canonicalconstraints.g

@@ -20,6 +20,8 @@ BTKit_Con.InCosetSimple := function(n, group, perm)
 
     r := rec(
         name := "InGroupSimple",
+        largest_required_point := Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
+        largest_moved_point :=  Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
         image := {p} -> RightCoset(group, p),
         result := {} -> RightCoset(group, perm),
         check := {p} -> p in RightCoset(group, perm),

gap/constraints/conjugacyexample.g

@@ -3,6 +3,7 @@
 BTKit_Con.MostBasicPermConjugacy := function(permL, permR)
     return Objectify(BTKitRefinerType,rec(
         name := "MostBasicPermConjugacy",
+        largest_required_point := Maximum(LargestMovedPoint(permL),LargestMovedPoint(permR)),
         image := {p} -> permL^p,
         result := {} -> permR,
         refine := rec(
@@ -32,6 +33,7 @@ BTKit_Con.BasicPermConjugacy := function(permL, permR)
 
     return Objectify(BTKitRefinerType,rec(
         name := "BasicPermConjugacy",
+        largest_required_point := Maximum(LargestMovedPoint(permL),LargestMovedPoint(permR)),
         image := {p} -> permL^p,
         result := {} -> permR,
         refine := rec(
@@ -85,6 +87,7 @@ BTKit_Con.PermTransporter := function(n, fixedeltL, fixedeltR)
 
 
     r := rec( name := "PermTransporter",
+              largest_required_point := Maximum(LargestMovedPoint(fixedeltL),LargestMovedPoint(fixedeltR)),
               image := {p} -> fixedeltL^p,
               result := {} -> fixedeltR,
               refine := rec( initialise := function(ps, buildingRBase)

gap/constraints/graphconstraints.g

@@ -37,6 +37,7 @@ BTKit_Con.GraphTrans := function(graphL, graphR)
             end;
     return Objectify(BTKitRefinerType, rec(
         name := "GraphTrans",
+        largest_required_point := Maximum(Maximum(DigraphVertices(graphL), Maximum(DigraphVertices(graphR)))),
         image := {p} -> OnDigraphs(graphL, p),
         result := {} -> graphR,
         refine := rec(

gap/constraints/normaliserexample.g

@@ -7,6 +7,7 @@
 BTKit_Con.MostBasicGroupConjugacy := function(grpL, grpR)
     return Objectify(BTKitRefinerType,rec(
         name := "MostBasicGroupPermConjugacy",
+        largest_required_point := Maximum(LargestMovedPoint(grpL), LargestMovedPoint(grpR)),
         image := {p} -> grpL^p,
         result := {} -> grpR,
         refine := rec(
@@ -36,6 +37,7 @@ BTKit_Con.BasicGroupConjugacy := function(grpL, grpR)
 
     return Objectify(BTKitRefinerType,rec(
         name := "BasicGroupConjugacy",
+        largest_required_point := Maximum(LargestMovedPoint(grpL), LargestMovedPoint(grpR)),
         image := {p} -> grpL^p,
         result := {} -> grpR,
         refine := rec(
@@ -67,6 +69,7 @@ BTKit_Con.SimpleGroupConjugacy := function(grpL, grpR)
 
     return Objectify(BTKitRefinerType,rec(
         name := "BasicGroupConjugacy",
+        largest_required_point := Maximum(LargestMovedPoint(grpL), LargestMovedPoint(grpR)),
         image := {p} -> grpL^p,
         result := {} -> grpR,
         refine := rec(

gap/constraints/simpleconstraints.g

@@ -20,6 +20,7 @@ BTKit_MakeFixlistStabilizer := function(name, fixlist, o, action)
     filters := {i} -> fixlist[i];
     return Objectify(BTKitRefinerType, rec(
         name := name,
+        largest_required_point := Length(o),
         image := {p} -> action(o,p),
         result := {} -> o,
         refine := rec(
@@ -37,6 +38,7 @@ BTKit_MakeFixlistTransporter := function(name, fixlistL, fixlistR, oL, oR, actio
     filtersR := {i} -> fixlistR[i];
     return Objectify(BTKitRefinerType, rec(
         name := name,
+        largest_required_point := Length(oL),
         image := {p} -> action(oL,p),
         result := {} -> oR,
         refine := rec(
@@ -176,6 +178,8 @@ BTKit_Con.InCoset := function(n, group, perm)
 
     r := rec(
         name := "InCoset",
+        largest_required_point := Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
+        largest_moved_point :=  Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
         image := {p} -> RightCoset(group, p),
         result := {} -> RightCoset(group, perm),
         check := {p} -> p in RightCoset(group, perm),
@@ -292,7 +296,8 @@ BTKit_Con.InCosetWithOrbitals := function(n, group, perm)
 
     r := rec(
         name := "InGroupWithCoset-BTKit",
-
+        largest_required_point := Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
+        largest_moved_point :=  Maximum(LargestMovedPoint(group), LargestMovedPoint(perm)),
         image := {p} -> RightCoset(group, p),
         result := {} -> RightCoset(group, perm),
         check := {p} -> p in RightCoset(group, perm),
@@ -357,6 +362,8 @@ BTKit_Con.InGroupWithOrbitals := {n, group} -> BTKit_Con.InCosetWithOrbitals(n,
 
 BTKit_Con.Nothing := {} -> Objectify(BTKitRefinerType, rec(
         name := "Nothing",
+        largest_required_point := 1,
+        largest_moved_point := 1,
         image := {p} -> true,
         result := {} -> false,
         refine := rec(
@@ -368,6 +375,8 @@ BTKit_Con.Nothing := {} -> Objectify(BTKitRefinerType, rec(
 
 BTKit_Con.Nothing2 := {} -> Objectify(BTKitRefinerType, rec(
         name := "Nothing2",
+        largest_required_point := 1,
+        largest_moved_point := 1,
         image := {p} -> true,
         result := {} -> false,
         refine := rec(

tst/basic.tst

@@ -12,7 +12,7 @@ gap> G := BTKit_SimpleSearch(ps3, [BTKit_Con.InGroup(3, SymmetricGroup(3))]);;
 gap> G = SymmetricGroup(3);
 true
 gap> G := BTKit_SimpleSearch(ps3, [BTKit_Con.InGroup(3, Group((1,2)(3,4)))]);
-Group(())
+Error, Refiner InCoset requires 4 points, but the partition only has 3
 gap> G := BTKit_SimpleSearch(ps6, [BTKit_Con.InGroup(6, AlternatingGroup(6)),
 >                                  BTKit_Con.SetStab(6, [2,4,6]),
 >                                  BTKit_Con.TupleStab(6, [1,2])]);;