Generated from pttp-dalit.pl with ROBODoc v3.2.4 on Thu Apr 08 19:27:54 2004
TABLE OF CONTENTS
- PTTP/PTTP-dalit
COPYRIGHT
Copyright (c) 1988-2003 Mark E. Stickel, SRI International, Menlo Park, CA 94025 USA
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
DESCRIPTION
A Prolog Technology Theorem Prover
Mark E. Stickel
This file contains changes to PTTP to use
depth-first iterative deepening search with bound on
D_Alit (maximum number of A-literals on a branch)
instead of
D_Inf (total number of subgoals).
To use, load pttp and then load this file
to replace changed definitions.
SOURCE
prove(Goal,Max,Min,Inc,ProofIn,ProofOut) :-
expand_input_proof(ProofIn,PrfEnd),
PrevInc is Min + 1,
add_args(Goal,_,_,[],_,_,[],[],DepthIn,[PrfEnd|PrfEnd],ProofOut1,Goal1,_),
!,
timed_call(search(Goal1,Max,Min,Inc,PrevInc,DepthIn),'Proof'),
contract_output_proof(ProofOut1,ProofOut),
write_proof(ProofOut1),
nl.
prove(Goal,Max,Min,Inc,ProofIn) :-
prove(Goal,Max,Min,Inc,ProofIn,_).
prove(Goal,Max,Min,Inc) :-
prove(Goal,Max,Min,Inc,[],_).
prove(Goal,Max,Min) :-
prove(Goal,Max,Min,1,[],_).
prove(Goal,Max) :-
prove(Goal,Max,0,1,[],_).
prove(Goal) :-
prove(Goal,10000,0,1,[],_).
search_cost(Body,HeadArgs,N) :-
Body = search_cost(M) ->
N = M;
Body = (A , B) ->
(A = search_cost(M) -> % if first conjunct is search_cost(M),
N = M; % search cost of conjunction is M
%true ->
search_cost(A,HeadArgs,N1),
search_cost(B,HeadArgs,N2),
max(N1,N2,N));
Body = (A ; B) ->
search_cost(A,HeadArgs,N1),
search_cost(B,HeadArgs,N2),
min(N1,N2,N);
builtin(Body) ->
N = 0;
%true ->
N = 1.
search(_Goal,Max,Min,_Inc,_PrevInc,_DepthIn) :-
Min > Max,
!,
fail.
search(Goal,_Max,Min,_Inc,PrevInc,DepthIn) :-
write_search_progress(Min),
DepthIn = Min,
call(Goal),
true. % should fail if solution found previously
search(Goal,Max,Min,Inc,_PrevInc,DepthIn) :-
Min1 is Min + Inc,
search(Goal,Max,Min1,Inc,Inc,DepthIn).
make_wrapper(_DefinedPreds,[query,0],true) :-
!.
make_wrapper(DefinedPreds,[P,N],Result) :-
functor(Goal,P,N),
Goal =.. [P|Args],
ExtraArgs = [PosAncestors,NegAncestors,DepthIn,ProofIn,ProofOut],
list_append(Args,ExtraArgs,Args1),
Head =.. [P|Args1],
internal_functor(P,IntP),
list_length(ExtraArgs,NExtraArgs),
NN is N + NExtraArgs + 1,
(identical_member([IntP,NN],DefinedPreds) ->
list_append(ExtraArgs,[GoalAtom],ExtraArgs2),
list_append(Args,ExtraArgs2,Args2),
IntHead =.. [IntP|Args2];
%true ->
IntHead = fail),
(negative_functor(P) ->
negated_literal(Goal,PosGoal),
Red = redn, % atom in proof is negation of actual literal
C1Ancestors = NegAncestors,
C2Ancestors = PosAncestors;
%true ->
PosGoal = Goal,
Red = red,
C1Ancestors = PosAncestors,
C2Ancestors = NegAncestors),
(N = 0 -> % special case for propositional calculus
V1 = (identical_member(GoalAtom,C2Ancestors) , !);
%true ->
V1 = ((identical_member(GoalAtom,C2Ancestors) , !);
unifiable_member(GoalAtom,C2Ancestors))),
V2 = (
ProofIn = [Prf,[Red,GoalAtom,PosAncestors,NegAncestors]|PrfEnd],
ProofOut = [Prf|PrfEnd]),
conjoin(V1,V2,Reduce),
Result = (Head :- GoalAtom = PosGoal,
(identical_member(GoalAtom,C1Ancestors) ->
fail;
%true ->
(Reduce;
IntHead))).
query(PosAncestors,NegAncestors,DepthIn,ProofIn,ProofOut) :-
int_query(PosAncestors,NegAncestors,DepthIn,ProofIn,ProofOut,query).
add_features((Head :- Body),(Head1 :- Body1)) :-
(functor(Head,query,_) ->
Head2 = Head,
add_args(Body,yes,query,[],
PosAncestors,NegAncestors,
PosAncestors,NegAncestors,
DepthIn,
ProofIn,ProofOut,
Body1,_);
%true ->
linearize(Head,Head2,[],_,true,Matches),
(negative_literal(Head) ->
PosGoal = no;
%true ->
PosGoal = yes),
Head =.. [_|HeadArgs],
add_args(Body,PosGoal,GoalAtom,HeadArgs,
PosAncestors,NegAncestors,
NewPosAncestors,NewNegAncestors,
Depth1,
ProofIn,ProofOut,
Body2,New),
(var(New) ->
PushAnc = true;
PosGoal = yes ->
NewNegAncestors = NegAncestors,
PushAnc = (NewPosAncestors = [GoalAtom|PosAncestors]);
%true ->
NewPosAncestors = PosAncestors,
PushAnc = (NewNegAncestors = [GoalAtom|NegAncestors])),
search_cost(Body,HeadArgs,Cost),
test_and_decrement_search_cost_expr(DepthIn,Cost,Depth1,TestExp),
conjoin(PushAnc,Body2,Body4),
conjoin(Matches,Body4,Body5),
conjoin(TestExp,Body5,Body1)),
Head2 =.. [P|L],
internal_functor(P,IntP),
list_append(L,[PosAncestors,NegAncestors,
DepthIn,
ProofIn,ProofOut,
GoalAtom],
L1),
Head1 =.. [IntP|L1].
add_args(Body,PosGoal,GoalAtom,HeadArgs,
PosAncestors,NegAncestors,
NewPosAncestors,NewNegAncestors,
DepthIn,
ProofIn,ProofOut,
Body1,New) :-
Body = (A , B) ->
add_args(A,PosGoal,GoalAtom,HeadArgs,
PosAncestors,NegAncestors,
NewPosAncestors,NewNegAncestors,
DepthIn,
ProofIn,Proof1,
A1,New),
add_args(B,PosGoal,GoalAtom,HeadArgs,
PosAncestors,NegAncestors,
NewPosAncestors,NewNegAncestors,
DepthIn,
Proof1,ProofOut,
B1,New),
conjoin(A1,B1,Body1);
Body = (A ; B) ->
unimplemented;
functor(Body,search_cost,_) ->
ProofOut = ProofIn,
Body1 = true;
Body = infer_by(N) ->
(PosGoal = yes ->
N1 = N;
%true -> % atom in proof is negation of actual literal
N1 is - N),
Body1 = (ProofIn = [Prf,[N1,GoalAtom,PosAncestors,NegAncestors]|PrfEnd],
ProofOut = [Prf|PrfEnd]);
Body = search_cost(N) ->
ProofOut = ProofIn,
Body1 = true;
builtin(Body) ->
ProofOut = ProofIn,
Body1 = Body;
%true ->
Body =.. L,
list_append(L,
[NewPosAncestors,NewNegAncestors,
DepthIn,
ProofIn,ProofOut],
L1),
Body1 =.. L1,
New = yes.