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