diff --git a/packages/CLPBN/Makefile.in b/packages/CLPBN/Makefile.in
index 5eaa9445e..b8bcde77a 100644
--- a/packages/CLPBN/Makefile.in
+++ b/packages/CLPBN/Makefile.in
@@ -57,6 +57,7 @@ CLPBN_PROGRAMS= \
 	$(CLPBN_SRCDIR)/horus_lifted.yap \
 	$(CLPBN_SRCDIR)/jt.yap \
 	$(CLPBN_SRCDIR)/matrix_cpt_utils.yap \
+	$(CLPBN_SRCDIR)/numbers.yap \
 	$(CLPBN_SRCDIR)/pgrammar.yap \
 	$(CLPBN_SRCDIR)/table.yap \
 	$(CLPBN_SRCDIR)/topsort.yap \
diff --git a/packages/CLPBN/clpbn/numbers.yap b/packages/CLPBN/clpbn/numbers.yap
new file mode 100644
index 000000000..6122b89d3
--- /dev/null
+++ b/packages/CLPBN/clpbn/numbers.yap
@@ -0,0 +1,60 @@
+
+:- module(clpbn_numbers,
+	[
+         keys_to_numbers/7, 
+         keys_to_numbers/9, 
+	 lists_of_keys_to_ids/6
+     ]).
+
+:- use_module(library(bhash)).
+:- use_module(library(maplist)).
+:- use_module(library(pfl),
+          [skolem/2,
+           get_pfl_cpt/5
+          ]).
+
+%
+% convert key representation into numeric representation
+% (+keys, +all factors, +all evidence, -ConvTable, -NextId, -FactorsWithIds, -EvidenceWithIds)
+%
+keys_to_numbers(AllKeys, Factors, Evidence, Hash, Id4, FactorIds, EvidenceIds) :-
+	b_hash_new(Hash0),
+	keys_to_numbers(AllKeys, Factors, Evidence, Hash0, Hash, 0, Id4, FactorIds, EvidenceIds).
+
+
+keys_to_numbers(AllKeys, Factors, Evidence, Hash0, Hash4, Id0, Id4, FactorIds, EvidenceIds) :-
+	foldl2(key_to_id, AllKeys, _Ids, Hash0, Hash1, Id0, Id1),
+	foldl2(evidence_to_id, Evidence, EvidenceIds, Hash1, Hash2, Id1, Id2),
+	foldl2(factor_to_id(Evidence), Factors, FactorIds, Hash2, Hash3, Id2, Id3),
+	sort(AllKeys,SKeys), %% writeln(allSortedKeys:SKeys), writeln(''),
+	foldl2(key_to_id, SKeys, _, Hash3, Hash4, Id3, Id4).
+
+lists_of_keys_to_ids(QueryKeys, QueryIds, Hash0, Hash, Id0, Id) :-
+        foldl2(list_of_keys_to_ids, QueryKeys, QueryIds, Hash0, Hash, Id0, Id).
+
+list_of_keys_to_ids(List, IdList, Hash0, Hash, I0, I) :-
+	foldl2(key_to_id, List, IdList, Hash0, Hash, I0, I).
+
+key_to_id(Key, Id, Hash0, Hash0, I0, I0) :-
+    b_hash_lookup(Key, Id, Hash0), !.
+key_to_id(Key, I0, Hash0, Hash, I0, I) :-
+    b_hash_insert(Hash0, Key, I0, Hash),
+    I is I0+1.
+
+factor_to_id(Ev, f(_, DistId, Keys), f(Ids, Ranges, CPT, DistId), Hash0, Hash, I0, I) :-
+	get_pfl_cpt(DistId, Keys, Ev, NKeys, CPT),
+	foldl2(key_to_id, NKeys, Ids, Hash0, Hash, I0, I),
+	maplist(get_range, Keys, Ranges).
+
+get_range(K, Range) :-
+	skolem(K,Domain),
+	length(Domain,Range).
+
+
+evidence_to_id(Key=Ev, Id=Ev, Hash0, Hash0, I0, I0) :-
+	b_hash_lookup(Key, Id, Hash0), !.
+evidence_to_id(Key=Ev, I0=Ev, Hash0, Hash, I0, I) :-
+	b_hash_insert(Hash0, Key, I0, Hash),
+	I is I0+1.
+
+