diff --git a/CXX/yapi.cpp b/CXX/yapi.cpp
index a8601a122..6c5b4030e 100644
--- a/CXX/yapi.cpp
+++ b/CXX/yapi.cpp
@@ -252,10 +252,11 @@ YAPStringTerm::YAPStringTerm(wchar_t *s, size_t len)
 YAPApplTerm::YAPApplTerm(YAPFunctor f, YAPTerm ts[]) {
   BACKUP_H();
   arity_t arity = ArityOfFunctor(f.f);
-  Term o = Yap_MkNewApplTerm(f.f, arity);
+  Term o = AbsAppl(HR);
+  *HR++ = (CELL)f.f;
   Term *tt = RepAppl(o) + 1;
   for (arity_t i = 0; i < arity; i++)
-    tt[i] = ts[i].term();
+    *HR++ = ts[i].term();
   mk(o);
   RECOVER_H();
 }
diff --git a/docker/Dockerfile b/docker/Dockerfile
new file mode 100644
index 000000000..875663fd3
--- /dev/null
+++ b/docker/Dockerfile
@@ -0,0 +1,42 @@
+# Use an official Python runtime as a parent image
+FROM ubuntu:18.04
+
+# Update Software repository
+RUN apt-get update
+ 
+
+# Set the working directory to /app
+WORKDIR /app
+
+# Copy the current directory contents into the container at /app
+COPY . /app
+
+# Install any needed packages specified in requirements.txt
+RUN apt install gcc g++ libreadline-dev libgmp-dev git \
+    python3-dev python3-pip  python3-notebook python3-wheel python3-setuptools\
+    libgecode-dev r-cran-rcpp cmake libbdd-dev libxml2-dev \
+    bison flex openjdk-11-jdk-headless libraptor2-dev swig
+
+#RUN git clone ssh://vsc@ssh.dcc.fc.up.pt:31064/yap.git
+RUN git clone https://github.com/vscosta/cudd.git
+RUN git clone https://github.com/vscosta/doxygen-yap.git
+RUN git clone https://github.com/vscosta/cudd.git
+
+RUN pushd cudd; ./configure --prefix=/usr --enable-shared --enable-obj --enable-dddmp; make -j install; popd
+
+RUN pushd doxygen-yap; mkdir -p build; cd build; cmake .. -DCMAKE_INSTALL_PREFIX:PATH=/usr && cmake --build . --target install; popd
+
+RUN pushd yap; mkdir -p build; cd build; cmake .. -DCMAKE_INSTALL_PREFIX:PATH=/usr && cmake --build . --target install; pushd paackages/real; R CMD INSTALL yap4r; popd; popd
+
+RUN R CMD INSTALL packages/real/yap4r
+
+# Make port 80 available to the world outside this container
+EXPOSE 80
+
+# Define environment variable
+ENV NAME World
+
+# Run app.py when the container launches
+CMD ["python", "app.py"]
+This Dockerfile refers to a couple of files we haven’t created yet, namely app.py and requirements.txt. Let’s create those next.
+
diff --git a/packages/ProbLog/problog_examples/kbgraph.yap b/packages/ProbLog/problog_examples/kbgraph.yap
index f1b6e0eb6..5bb2b22fb 100644
--- a/packages/ProbLog/problog_examples/kbgraph.yap
+++ b/packages/ProbLog/problog_examples/kbgraph.yap
@@ -41,7 +41,7 @@ cvt_to_id([E0,E1],VId*true, [Id-VId]) :-
 cvt_to_id([E0,E1|Es], VId*Ids, [Id-VId|VIds]) :-
    problog:problog_dir_edge(Id,E0,E1,_Pr),
     !,
-    cvt_to_id([E1|Es],Id*Ids, VIds).
+    cvt_to_id([E1|Es],Ids, VIds).
 cvt_to_id([E0,E1|Es],  VId*Ids, [Id-VId|VIds]) :-
    problog:problog_dir_edge(Id,E1,E0,_Pr),
     !,
diff --git a/packages/ProbLog/problog_lbfgs.yap b/packages/ProbLog/problog_lbfgs.yap
index 028227a6f..8aebc52bc 100644
--- a/packages/ProbLog/problog_lbfgs.yap
+++ b/packages/ProbLog/problog_lbfgs.yap
@@ -489,7 +489,8 @@ init_learning :-
 	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 	% build BDD script for every example
         %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-	once(init_queries),
+	empty_bdd_directory,
+	init_queries,
 
 	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 	% done
@@ -550,7 +551,7 @@ empty_bdd_directory.
 
 
 init_queries :-
-    %empty_bdd_directory,
+    empty_bdd_directory,
 	format_learning(2,'Build BDDs for examples~n',[]),
 	forall(user:test_example(ID,Query,_Prob,_),init_one_query(ID,Query,test)),	
 	forall(user:example(ID,Query,_Prob,_),init_one_query(ID,Query,training)).
@@ -584,6 +585,7 @@ init_one_query(QueryID,Query,_Type) :-
     add_bdd(QueryID,Query, Bdd) :-
 	Bdd = bdd(Dir, Tree0,MapList),
 	user:graph2bdd(Query,1,Bdd),
+	Bdd \= [],
 	!,
 	 reverse(Tree0,Tree),
  	  %rb_new(H0),
@@ -592,21 +594,12 @@ init_one_query(QueryID,Query,_Type) :-
 	  % ;
 	  % Bdd = bdd(-1,[],[]),
 	  % Grad=[]
-	  store_bdd(QueryID, Dir, Tree, MapList).
-init_one_query(_,_,_).
+	 store_bdd(QueryID, Dir, Tree, MapList).
 
 store_bdd(QueryID, Dir, Tree, MapList) :-
 	 (QueryID mod 100 =:= 0 ->writeln(QueryID) ; true),
-	  (
-	    recorded(QueryID, Bdd0, R),
-	    arg(3, Bdd0, MapList0),  				variant(MapList0,MapList)
-	    ->
-	    put_char('.')
-	    ;
-	    (nonvar(R) -> erase(R);true),
 	    recorda(QueryID,bdd(Dir, Tree, MapList),_),
-	    put_char('.')
-	).
+	    put_char('.').
 
 
 %========================================================================
@@ -786,11 +779,9 @@ inv_sigmoid(T,Slope,InvSig) :-
 
 % vsc: avoid silly search
 gradient_descent :-
-    problog_flag(sigmoid_slope,Slope),
-%	current_iteration(Iteration),
     findall(FactID,tunable_fact(FactID,_GroundTruth),L),
     length(L,N),
-    lbfgs_run(N,X,_BestF),
+    lbfgs_run(N,_X,_BestF),
     mse_trainingset,
     mse_testset.
 
@@ -830,8 +821,15 @@ user:evaluate(LLH_Training_Queries, X,Grad,N,_,_) :-
     %Handle = user_error,
     N1 is N-1,
     forall(between(0,N1,I),(Grad[I]<==0.0)),
-    go( X,Grad, LLs),
-    sum_list( LLs, LLH_Training_Queries).
+    catch(
+	go( X,Grad, LLs),
+	Error,
+	(writeln(Error), throw(Error) )),
+   length(LLs,NN),
+   V <== array[NN] of LLs,
+   SLL <== sum(V),
+    %sum_list( LLs, SLL),
+    LLH_Training_Queries[0] <== SLL.
 
 test :-
     S =.. [f,0-0.9,1-0.8,2-0.6,3-0.7,4-0.5,5-0.4,6-0.7,7-0.2],
@@ -845,7 +843,8 @@ Grad <== array[N] of floats,
 	LL,
 	compute_gradient(Grad, X, Slope,LL),
 	LLs
- ), sum_list( LLs, _LLH_Training_Queries).
+ ), sum_list( LLs, SLL).
+
 
 
 
@@ -862,8 +861,12 @@ compute_gradient( Grad, X, Slope, LL) :-
   	user:example(QueryID,_Query,QueryProb,_),
 	recorded(QueryID,BDD,_),
 	BDD = bdd(_,_,MapList),
+	MapList = [_|_],
 	bind_maplist(MapList, Slope, X),
+%writeln(QueryID:MapList),
 	query_probabilities( BDD, BDDProb),
+	(isnan(BDDProb) -> writeln((nan::QueryID)), fail;true),
+writeln(BDDProb),
 	LL is (BDDProb-QueryProb)*(BDDProb-QueryProb),
     forall(
 	query_gradients(BDD,I,IProb,GradValue), 
@@ -873,6 +876,7 @@ compute_gradient( Grad, X, Slope, LL) :-
 gradient_pair(BDDProb, QueryProb, Grad, GradValue, I, Prob) :-
     G0 <== Grad[I],
     GN is G0-GradValue*Prob*(1-Prob)*2*(QueryProb-BDDProb),
+    (isnan(GN) -> writeln((nan::I)), fail;true),
     Grad[I] <== GN.
 
 wrap( X, Grad, GradCount) :-
diff --git a/packages/yap-lbfgs/yap_lbfgs.c b/packages/yap-lbfgs/yap_lbfgs.c
index b513b77c1..7a7712d85 100644
--- a/packages/yap-lbfgs/yap_lbfgs.c
+++ b/packages/yap-lbfgs/yap_lbfgs.c
@@ -42,13 +42,14 @@ static lbfgsfloatval_t evaluate(void *instance, const lbfgsfloatval_t *x,
                                 const lbfgsfloatval_t step) {
   YAP_Term call;
   YAP_Bool result;
-  lbfgsfloatval_t rc;
+  lbfgsfloatval_t rc=0.0;
   YAP_Term v, t1, t12;
   YAP_Term t[6], t2[2];
 
-  t[0] = v = YAP_MkVarTerm();
-  t1 = YAP_MkIntTerm((YAP_Int)x);
-  t[1] = YAP_MkApplTerm(ffloats, 1, &t1);
+  YAP_Term t_0 = YAP_MkIntTerm((YAP_Int)&rc);
+  t[0] = YAP_MkApplTerm(ffloats, 1, &t_0);
+  YAP_Term t_1 = YAP_MkIntTerm((YAP_Int)x);
+  t[1] = YAP_MkApplTerm(ffloats, 1, &t_1);
   t12 = YAP_MkIntTerm((YAP_Int)g_tmp);
   t[2] = YAP_MkApplTerm(ffloats, 1, &t12);
   t[3] = YAP_MkIntTerm(n);
@@ -70,12 +71,9 @@ static lbfgsfloatval_t evaluate(void *instance, const lbfgsfloatval_t *x,
     // Goal did not succeed
     return FALSE;
   }
-  YAP_Term o;
-  if (YAP_IsIntTerm((o = YAP_GetFromSlot(sl))))
-    rc = YAP_IntOfTerm(o);
-  else
-    rc = YAP_FloatOfTerm(o);
+   YAP_ShutdownGoal(true);
   YAP_RecoverSlots(1, sl);
+  fprintf(stderr,"%gxo\n",rc);
   return rc;
 }
 
@@ -123,9 +121,10 @@ static int progress(void *instance, const lbfgsfloatval_t *local_x,
 
   if (YAP_IsIntTerm(o)) {
     int v = YAP_IntOfTerm(o);
-    return (int)v;
+    YAP_ShutdownGoal(true);
+   return (int)v;
   }
-
+  YAP_ShutdownGoal(true);
   fprintf(stderr, "ERROR: The progress call back function did not return an "
                   "integer as last argument\n");
   return 1;