I am implementing an aggregation function in DC. The problem is that the head of the DC clause is not firing (the head random variable is not drawn from the probability distribution) when the body of the clause is true. The DC code is below:

%%% -- Mode: Prolog; --
:- use_module('../DC/dcpf.pl').
:- use_module('../DC/random/sampling.pl').
:- use_module('../DC/distributionalclause.pl').
:- use_module(library(lists)).
:- use_module(library(random)).

:- set_options(default).
:- set_inference(backward(lazy)).
:- initialization(init).

builtin(lmax( _ , _ )).
builtin(oneElementOfList( _ , _ )).

% Randomly picks one element of the list.
oneElementOfList([], []).
oneElementOfList(List, Elt) :- length(List, Length), random(0, Length, Index), nth0(Index, List, Elt).

% Finds a element occuring the most number of times in the list.
lmax(L, M) :- lmax(L, [], [], M).
lmax([], Seen, MMax, Max) :- MMax=[] -> Max=Seen; lmax(MMax, [], [], Max).
lmax([H|T], Seen, MMax, Max) :- (member(H, Seen) -> lmax(T, Seen, [H|MMax], Max); lmax(T, [H|Seen], MMax, Max)).
maxMod(X, P) ~ val(Max) := findall_forward(X,P,L), lmax(L, Max1), oneElementOfList(Max1, Max).

% Facts
marks(ann, bio) ~ val(high).
marks(ann, chem) ~ val(high).
marks(ann, phy) ~ val(low).

% Rule
grade(S) ~ finite([0.1:low, 0.9:high]) := maxMod(M, marks(S,C) ~= M) ~= high.

% Find probabilities
testMod(N) :-
query([],[],(maxMod(M, marks(ann,C) ~= M) ~= high),N,P),
write('probability: '),writeln(P).

testGrade(N) :-
query([],[],(grade(ann) ~= high),N,P),
write('probability: '),writeln(P).

After executing the above code I get
?- testMod(100).
probability: 1.0

?- testGrade(100).
probability: 0.0

Which means that the body is the clause "grade(S) ~ finite([0.1:low, 0.9:high]) := maxMod(M, marks(S,C) ~= M) ~= high." is always true but the head never fires.

I have invested a lot of time in resolving the issue but was not successful. Can you please check the issue?

Everytime I run any provided example, like yap -L examples/example1.pl, I get this permission error:

ERROR!! (/home/littlebrat/Git/DC/distributionalclause.pl:70).

PERMISSION ERROR- in line 70, system predicate abolish_all_tables: modifying static procedure abolish_all_tables/0

Absolute error drawn(1) ~= 1: 0.00138055555555389
Absolute error drawn(1) ~= 2: 0.00197777777777297
Absolute error drawn(1) ~= 3: 0.00067246031746343
Absolute error average g ~ Gaussian(0,0.1): 0.0018059877648761
% 0.176 CPU in 0.179 seconds ( 98% CPU)

I tried running it as a super user, but it also returns the same error. Is this expected behavior?

I got stucked at the 5th step of:
cd yap-6.3
mkdir arch
cd arch
../configure --enable-tabling=yes --enable-dynamic-loading
make
sudo make install
sudo make install_library

Output:
config.status: creating packages/clpqr/Makefile
config.status: creating packages/swi-minisat2/Makefile
config.status: creating packages/swi-minisat2/C/Makefile
config.status: creating packages/real/Makefile
config.status: creating packages/real/rconfig.h
config.status: creating packages/myddas/Makefile
config.status: creating packages/CLPBN/Makefile
config.status: creating packages/CLPBN/horus/Makefile
config.status: creating packages/prism/src/c/Makefile
config.status: creating packages/prism/src/prolog/Makefile
config.status: creating packages/yap-lbfgs/Makefile
config.status: creating config.h
config.status: creating YapTermConfig.h
config.status: YapTermConfig.h is unchanged
config.status: creating packages/raptor/raptor_config.h
config.status: packages/raptor/raptor_config.h is unchanged
yantian@yantian-Inspiron-7348:~/yap-6.3-master/arch$ make
make: *** No rule to make target H/dglobals.h', needed byyap'. Stop.

Thanks!