From 77722f0f871325ac417659b6c69eaa9ef7f5a922 Mon Sep 17 00:00:00 2001
From: "Jip J. Dekker" <jip@dekker.one>
Date: Mon, 26 Jul 2021 12:01:17 +1000
Subject: [PATCH] Fix the pareto front predicate

---
 assets/listing/inc_pareto.mzn | 13 ++++++++++++-
 chapters/5_incremental.tex    |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/assets/listing/inc_pareto.mzn b/assets/listing/inc_pareto.mzn
index 00d3fb1..f02e3fe 100644
--- a/assets/listing/inc_pareto.mzn
+++ b/assets/listing/inc_pareto.mzn
@@ -9,11 +9,22 @@ predicate pareto_optimal(var int: obj1, var int: obj2) =
 		nsol = 0
 	elseif status() = UNSAT then
 		complete()        % we are finished!
-	elseif
+	elsif status() = SAT then
 		nsol = sol(nsol) + 1 /\
 		s1[nsol] = sol(obj1) /\
 		s2[nsol] = sol(obj2)
 	endif
 	/\ for(i in 1..nsol) (
 		obj1 < lastval(s1[i]) \/ obj2 < lastval(s2[i])
+	) /\ for(i in 1..ms) (
+		if i in 1..nsol-1 then
+			s1[i] = lastval(s1[i]) /\ 
+			s2[i] = lastval(s2[i]) /\ 
+		elsif i = nsol /\ status() != SAT then
+			s1[i] = lastval(s1[i]) /\ 
+			s2[i] = lastval(s2[i]) /\ 
+		elseif i in nsol+1..ms then
+			s1[i] = lb(obj1) /\
+			s2[i] = lb(obj2)
+		endif
 	);
diff --git a/chapters/5_incremental.tex b/chapters/5_incremental.tex
index 1a740cf..d95acc2 100644
--- a/chapters/5_incremental.tex
+++ b/chapters/5_incremental.tex
@@ -266,6 +266,7 @@ If we do not find any \glspl{sol}, then we finish the entire search.
 Otherwise, we record that we have one more \gls{sol}.
 We store the \gls{sol} values in \mzninline{s1} and \mzninline{s2} \glspl{array}.
 Before each \gls{restart} we add \constraints{} removing Pareto dominated \glspl{sol}, based on each previous \gls{sol}.
+Additionally, we maintain the \glspl{sol} stored in \mzninline{s1} and \mzninline{s2} by assigning them to their previous value and avoid search on the unused spaces in the \glspl{array} by assignment them to the lower bound of their respective \gls{objective}.
 
 \section{Rewriting of Meta-Optimisation Algorithms}\label{sec:inc-solver-extension}