From d75f0ba437fea126fe32e438292b3e6885290894 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kamil=20=C5=9Aliwak?= <kamil.sliwak@codepoets.it>
Date: Fri, 11 Sep 2020 20:49:25 +0200
Subject: [PATCH] [yul-phaser] Chromosome: Make it possible to use genes that
 do not correspond to existing optimiser steps

---
 test/yulPhaser/Chromosome.cpp  |  9 +++++++++
 tools/yulPhaser/Chromosome.cpp |  5 +++++
 tools/yulPhaser/Chromosome.h   |  3 +++
 tools/yulPhaser/Mutations.cpp  | 32 ++++++++++++++++----------------
 4 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/test/yulPhaser/Chromosome.cpp b/test/yulPhaser/Chromosome.cpp
index 509ad0036..fd457645a 100644
--- a/test/yulPhaser/Chromosome.cpp
+++ b/test/yulPhaser/Chromosome.cpp
@@ -120,6 +120,15 @@ BOOST_AUTO_TEST_CASE(constructor_should_allow_duplicate_steps)
 	BOOST_TEST(Chromosome("ttfuf").genes() == "ttfuf");
 }
 
+BOOST_AUTO_TEST_CASE(constructor_should_allow_genes_that_do_not_correspond_to_any_step)
+{
+	assert(OptimiserSuite::stepAbbreviationToNameMap().count('.') == 0);
+	assert(OptimiserSuite::stepAbbreviationToNameMap().count('b') == 0);
+
+	BOOST_TEST(Chromosome(".").genes() == ".");
+	BOOST_TEST(Chromosome("a..abatbb").genes() == "a..abatbb");
+}
+
 BOOST_AUTO_TEST_CASE(output_operator_should_create_concise_and_unambiguous_string_representation)
 {
 	vector<string> allSteps;
diff --git a/tools/yulPhaser/Chromosome.cpp b/tools/yulPhaser/Chromosome.cpp
index c0e401800..687c669da 100644
--- a/tools/yulPhaser/Chromosome.cpp
+++ b/tools/yulPhaser/Chromosome.cpp
@@ -67,6 +67,11 @@ string const& Chromosome::randomOptimisationStep()
 	return stepNames[SimulationRNG::uniformInt(0, stepNames.size() - 1)];
 }
 
+char Chromosome::randomGene()
+{
+	return OptimiserSuite::stepNameToAbbreviationMap().at(randomOptimisationStep());
+}
+
 string Chromosome::stepsToGenes(vector<string> const& _optimisationSteps)
 {
 	string genes;
diff --git a/tools/yulPhaser/Chromosome.h b/tools/yulPhaser/Chromosome.h
index 0e7d1bb3f..96477086f 100644
--- a/tools/yulPhaser/Chromosome.h
+++ b/tools/yulPhaser/Chromosome.h
@@ -44,6 +44,8 @@ public:
 	explicit Chromosome(std::vector<std::string> _optimisationSteps):
 		m_genes(stepsToGenes(_optimisationSteps)) {}
 	explicit Chromosome(std::string _genes):
+		// NOTE: We don't validate the genes - they're only checked at the point of conversion to
+		// actual optimisation steps names. This is very convenient in mutation tests.
 		m_genes(std::move(_genes)) {}
 	static Chromosome makeRandom(size_t _length);
 
@@ -58,6 +60,7 @@ public:
 	bool operator!=(Chromosome const& _other) const { return !(*this == _other); }
 
 	static std::string const& randomOptimisationStep();
+	static char randomGene();
 	static std::string stepsToGenes(std::vector<std::string> const& _optimisationSteps);
 	static std::vector<std::string> genesToSteps(std::string const& _genes);
 
diff --git a/tools/yulPhaser/Mutations.cpp b/tools/yulPhaser/Mutations.cpp
index 61614408d..3e3e91b28 100644
--- a/tools/yulPhaser/Mutations.cpp
+++ b/tools/yulPhaser/Mutations.cpp
@@ -36,15 +36,15 @@ function<Mutation> phaser::geneRandomisation(double _chance)
 {
 	return [=](Chromosome const& _chromosome)
 	{
-		vector<string> optimisationSteps;
-		for (auto const& step: _chromosome.optimisationSteps())
-			optimisationSteps.push_back(
+		string genes;
+		for (char gene: _chromosome.genes())
+			genes.push_back(
 				SimulationRNG::bernoulliTrial(_chance) ?
-				Chromosome::randomOptimisationStep() :
-				step
+				Chromosome::randomGene() :
+				gene
 			);
 
-		return Chromosome(move(optimisationSteps));
+		return Chromosome(move(genes));
 	};
 }
 
@@ -52,12 +52,12 @@ function<Mutation> phaser::geneDeletion(double _chance)
 {
 	return [=](Chromosome const& _chromosome)
 	{
-		vector<string> optimisationSteps;
-		for (auto const& step: _chromosome.optimisationSteps())
+		string genes;
+		for (char gene: _chromosome.genes())
 			if (!SimulationRNG::bernoulliTrial(_chance))
-				optimisationSteps.push_back(step);
+				genes.push_back(gene);
 
-		return Chromosome(move(optimisationSteps));
+		return Chromosome(move(genes));
 	};
 }
 
@@ -65,19 +65,19 @@ function<Mutation> phaser::geneAddition(double _chance)
 {
 	return [=](Chromosome const& _chromosome)
 	{
-		vector<string> optimisationSteps;
+		string genes;
 
 		if (SimulationRNG::bernoulliTrial(_chance))
-			optimisationSteps.push_back(Chromosome::randomOptimisationStep());
+			genes.push_back(Chromosome::randomGene());
 
-		for (auto const& step: _chromosome.optimisationSteps())
+		for (char gene: _chromosome.genes())
 		{
-			optimisationSteps.push_back(step);
+			genes.push_back(gene);
 			if (SimulationRNG::bernoulliTrial(_chance))
-				optimisationSteps.push_back(Chromosome::randomOptimisationStep());
+				genes.push_back(Chromosome::randomGene());
 		}
 
-		return Chromosome(move(optimisationSteps));
+		return Chromosome(move(genes));
 	};
 }