1		% b_arithmetic_expressions.pl
2		% returns for arithmetic expressions a symbolic value that can be called in CLP(FD)
3
4		% :- use_module(kernel_waitflags,[add_error_wf/5]). included in b_interpreter
5
6		b_compute_arith_expression(b(Expr,Type,Info),LS,S,R,WF) :- !,
7		(ground(Type), Type == integer -> true
8		; add_error_wf(b_compute_arith_expression,'Arithmetic expression has illegal type: ',b(Expr,Type,Info),Info,WF)
9		),
10	?	b_compute_arith_expression2(Expr,Info,LS,S,R,WF).
11
12		b_compute_arith_expression(Expr,LS,S,R,WF) :-
13		add_error_wf(b_compute_arith_expression,'Expression not properly wrapped: ',Expr,Expr,WF),
14		b_compute_arith_expression2(Expr,unknown,LS,S,R,WF).
15
16
17		b_compute_arith_expression2(unary_minus(Arg1),_I,LocalState,State,Value,WF) :- !,
18		b_compute_arith_expression(Arg1,LocalState,State,SV1,WF),
19		Value = '-'(SV1).
20		b_compute_arith_expression2(add(Arg1,Arg2),_I,LocalState,State,Value,WF) :- !,
21	?	b_compute_arith_expression(Arg1,LocalState,State,SV1,WF),
22	?	b_compute_arith_expression(Arg2,LocalState,State,SV2,WF),
23		Value = '+'(SV1,SV2).
24		b_compute_arith_expression2(minus(Arg1,Arg2),_I,LocalState,State,Value,WF) :- !,
25	?	b_compute_arith_expression(Arg1,LocalState,State,SV1,WF),
26	?	b_compute_arith_expression(Arg2,LocalState,State,SV2,WF),
27		Value = '-'(SV1,SV2).
28		b_compute_arith_expression2(multiplication(Arg1,Arg2),_I,LocalState,State,Value,WF) :- !,
29	?	b_compute_arith_expression(Arg1,LocalState,State,SV1,WF),
30	?	b_compute_arith_expression(Arg2,LocalState,State,SV2,WF),
31		Value = '*'(SV1,SV2).
32		b_compute_arith_expression2(external_function_call(XFUN,[Arg1]),_Info,LocalState,State,Value,WF) :-
33		unary_external_function_to_clpfd(XFUN,SV1,ClpfdExpr),!,
34		b_compute_arith_expression(Arg1,LocalState,State,SV1,WF),
35		Value = ClpfdExpr.
36		b_compute_arith_expression2(Expr,Info,LocalState,State,Value,WF) :-
37	?	b_compute_expression2(Expr,integer,Info,LocalState,State,int(Value),WF).
38		%b_compute_expression2(Expr,integer,Info,LocalState,State,R,WF), R=int(Value). % this version does not seem faster
39		% kernel_objects:basic_type2(integer,int(Value)).
40
41		unary_external_function_to_clpfd('ABS',Arg1,abs(Arg1)).
42
43
44
45		% Note: calling b_compute_arith_expression will also instantiate a variable to at least the int(_) skeleton; thereby enabling propagation
46		% this is potentially better than calling the default versions of the predicates, which may wait until the int(_) skeleton is set up before propagation
47
48
49		:- use_module(clpfd_interface,[clpfd_eq_expr_optimized/2]).
50
51		b_test_arith_equal_boolean_expression(Arg1,Arg2,LocalState,State,WF) :-
52	?	b_compute_arith_expression(Arg1,LocalState,State,CLPFD_Expr1,WF),
53	?	b_compute_arith_expression(Arg2,LocalState,State,CLPFD_Expr2,WF),
54	?	clpfd_eq_expr_optimized(CLPFD_Expr1,CLPFD_Expr2).
55
56		%(preferences:preference(use_smt_mode,true)-> clpfd_eq_expr_optimized(CLPFD_Expr1,CLPFD_Expr2)
57		% ; clpfd_eq_expr(CLPFD_Expr1,CLPFD_Expr2)).
58		% maybe we should call clpfd_eq_expr_optimized only in SMT mode and call clpfd_eq_expr otherwise ??
59		% initially test 1077 ran considerably slower with clpfd_eq_expr_optimized