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Merge pull request #2970 from notoria/clpz

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Make `(mod)/2` stronger in CLP(Z)
This commit is contained in:
Mark Thom
2025-06-16 21:02:38 -07:00
committed by GitHub
parent 686f20db74 4b480a7eab
commit 1cf5de8f5c
1 changed files with 39 additions and 4 deletions
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43
src/lib/clpz.pl
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@@ -5088,11 +5088,21 @@ run_propagator(pmod(X,Y,Z), MState) -->
; nonvar(Z), nonvar(X) ->
( Z > 0 ->
( X < 0 -> true
; X >= Z
; X >= Z,
% due to X = Z+Y*_ and Y > Z
( X-Z > 0 ->
X-Z > Z
; true
)
)
; Z < 0 ->
( X > 0 -> true
; X =< Z
; X =< Z,
% due to X = Z+Y*_ and Y < Z
( X-Z < 0 ->
X-Z < Z
; true
)
)
; Z =:= 0 % Multiple solutions so do nothing special.
),
@@ -5100,7 +5110,23 @@ run_propagator(pmod(X,Y,Z), MState) -->
YU < X, X =< 0 } -> kill(MState), Z =:= X
; { fd_get(Y, _, n(YL), _, _),
YL > X, X >= 0 } -> kill(MState), Z =:= X
; ( Z > 0 ->
; ( Z > 0, X < 0 ->
{ fd_get(Y, YD, YPs),
YMin is Z+1,
YMax is Z-X,
domain_remove_smaller_than(YD, YMin, YD1),
domain_remove_greater_than(YD1, YMax, YD2) },
fd_put(Y, YD2, YPs)
% queue_goal((Y #> Z, Y #=< Z-X))
; Z < 0, X > 0 ->
{ fd_get(Y, YD, YPs),
YMax is Z-1,
YMin is Z-X,
domain_remove_greater_than(YD, YMax, YD1),
domain_remove_smaller_than(YD1, YMin, YD2) },
fd_put(Y, YD2, YPs)
% queue_goal((Y #< Z, Y #>= Z-X))
; Z > 0 ->
{ fd_get(Y, YD, YPs),
YMin is Z + 1,
domain_remove_smaller_than(YD, YMin, YD1) },
@@ -5112,7 +5138,16 @@ run_propagator(pmod(X,Y,Z), MState) -->
domain_remove_greater_than(YD, YMax, YD1) },
fd_put(Y, YD1, YPs)
% queue_goal(Y #< Z)
; true
; Z =:= 0,
( X =:= 0 ->
kill(MState) % trivial
; % only 4 solutions {-abs(X),-1,1,abs(X)}
{ YL is -abs(X), YU is abs(X),
fd_get(Y, YD0, YPs),
domain_remove_smaller_than(YD0, YL, YD1),
domain_remove_greater_than(YD1, YU, YD) },
fd_put(Y, YD, YPs)
)
)
)
; run_propagator(pmodz(X,Y,Z), MState),