Convert Integers to access a random source

lib/integer.gi

@@ -1741,12 +1741,12 @@ NrBitsInt := function ( n )
  return nr;
 end;
 
-InstallMethod( Random,
- "for `Integers'",
- true,
- [ IsIntegers ], 0,
- function( Integers )
- return NrBitsInt( Random( [0..2^20-1] ) ) - 10;
+InstallMethodWithGlobalRandomGen(Random, 
+ "for a random source and `Integers'", true,
+ [IsRandomSource, IsIntegers],
+ 0,
+ function( rg, Integers )
+ return NrBitsInt( Random( rg, [0..2^20-1] ) ) - 10;
  end );
 
 

tst/testinstall/random.tst

@@ -0,0 +1,6 @@
+gap> START_TEST("random.tst");
+gap> Read( Filename( DirectoriesLibrary( "tst" ), "testrandom.g" ) );
+gap> randomTest(Integers, Random);
+gap> randomTest([1..10], Random);
+gap> randomTest([1,-6,"cheese", Group(())], Random);
+gap> STOP_TEST("random.tst", 1);

tst/testrandom.g

@@ -0,0 +1,83 @@
+randomTest := function(collection, method)
+ local test1, test2, test3, test4, test5, test6, localgen;
+ # Firstly, we will generate a base list
+ Init(GlobalMersenneTwister, 6);
+ test1 := List([1..1000], x -> method(collection));
+ # test2 should = test1
+ Init(GlobalMersenneTwister, 6);
+ test2 := List([1..1000], x -> method(collection));
+ # test3 should also = test1
+ Init(GlobalMersenneTwister, 6);
+ test3 := List([1..1000], x -> method(GlobalMersenneTwister, collection));
+ # test4 should be different (as it came from a different seed)
+ Init(GlobalMersenneTwister, 8);
+ test4 := List([1..1000], x -> method(collection));
+ # test5 should be the same as test4, as it is made from seed 8
+ # test6 should be the same as test1. Also, it checks that making test5
+ # did not touch the global source at all.
+ Init(GlobalMersenneTwister, 8);
+ localgen := RandomSource(IsMersenneTwister, 6);
+ test5 := List([1..1000], x -> method(localgen, collection));
+ test6 := List([1..1000], x -> method(collection));
+ if ForAny(Concatenation(test1, test2, test3, test4, test5, test6), x -> not (x in collection) ) then
+ Print("Random member outside collection: ", collection,"\n");
+ fi;
+ if test1 <> test2 then
+ Print("Random not repeatable: ", collection, "\n");
+ fi;
+ if test2 <> test3 then
+ Print("Random 2-arg vs 1-arg broken: ", collection, "\n");
+ fi;
+ if test1 = test4 then
+ Print("Random not changing with random seed: ", collection, "\n");
+ fi;
+ if test1 <> test5 then
+ Print("Alt gen broken: ", collection, "\n");
+ fi;
+ if test4 <> test6 then
+ Print("Random with a passed in seed effects the global generator: ", collection, "\n");
+ fi;
+end;;
+
+# A special test for collections of size 1
+randomTestForSizeOneCollection := function(collection, method)
+ local i, val, localgen, intlist1, intlist2;
+ if Size(collection) <> 1 then
+ Print("randomTestForSizeOneCollection is only for collections of size 1");
+ return;
+ fi;
+
+ val := Representative(collection);
+
+ Init(GlobalMersenneTwister, 6);
+ intlist1 := List([1..1000], x -> Random([1..10]));
+
+ for i in [1..1000] do
+ if method(collection) <> val then
+ Print("Random returned something outside collection :", collection, ":", val);
+ fi;
+ od;
+
+ for i in [1..1000] do
+ if method(GlobalMersenneTwister, collection) <> val then
+ Print("Random returned something outside collection :", collection, ":", val);
+ fi;
+ od;
+
+ localgen := RandomSource(IsMersenneTwister, 6);
+
+ Init(GlobalMersenneTwister, 6);
+ for i in [1..1000] do
+ if method(localgen, collection) <> val then
+ Print("Random returned something outside collection :", collection, ":", val);
+ fi;
+ od;
+
+ # The previous loop should not have effected GlobalMersenneTwister,
+ # so this should be the same as intlist1
+ intlist2 := List([1..1000], x -> Random([1..10]));
+
+ if intlist1 <> intlist2 then
+ Print("Random read from local gen effected global gen: ", collection);
+ fi;
+end;;