Inverting density value when mapping to fitness

kataklinger · Mar 13, 2024 · 097ab8d · 097ab8d
1 parent c76b9d4
commit 097ab8d
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Showing 2 changed files with 31 additions and 26 deletions.
diff --git a/src/inc/projection.hpp b/src/inc/projection.hpp
@@ -35,7 +35,7 @@ class none {
   }
 };
 
-// x = f(rank) / (1 - density) (nsga)
+// x = rank / (1. - density) (nsga)
 template<typename RankTag>
 class scale {
 public:
@@ -73,7 +73,7 @@ class scale {
   }
 };
 
-// x = f(rank) + g(density) (spea-ii)
+// x = rank + (1. - density) (spea-ii)
 template<typename RankTag>
 class translate {
 public:
@@ -86,7 +86,7 @@ class translate {
 
     for (auto&& individual : context.population().individuals()) {
       auto rank = get_tag<RankTag>(individual).get();
-      auto density = get_tag<crowd_density_t>(individual).get();
+      auto density = 1. - get_tag<crowd_density_t>(individual).get();
 
       individual.eval().set_scaled(scaled_fitness_t{rank + density});
     }
@@ -109,7 +109,7 @@ class merge {
 
     for (auto&& individual : context.population().individuals()) {
       auto rank = get_tag<RankTag>(individual).get();
-      auto density = get_tag<crowd_density_t>(individual).get();
+      auto density = 1. - get_tag<crowd_density_t>(individual).get();
 
       individual.eval().set_scaled(scaled_fitness_t{rank, density});
     }
@@ -130,13 +130,18 @@ namespace details {
 
     for (auto&& individual : population.individuals()) {
       auto value = static_cast<double>(get_tag<Tag>(individual).get());
+
+      if constexpr (std::is_same_v<Tag, crowd_density_t>) {
+        value = 1. - value;
+      }
+
       individual.eval().set_scaled(scaled_fitness_t{value});
     }
   }
 
 } // namespace details
 
-// x = rank or x = density (pesa, paes)
+// x = rank or x = 1. - density (pesa, paes)
 template<typename SelectedTag>
 class truncate {
 public:
@@ -155,7 +160,7 @@ concept alternateable_context =
     population_tagged_with<typename Context::population_t, crowd_density_t> &&
     stats::tracked_models<typename Context::statistics_t, stats::generation>;
 
-// x0 = rank, x1 = density, ... (rdga)
+// x0 = rank, x1 = 1. - density, ... (rdga)
 template<typename RankTag>
 class alternate {
 public:

diff --git a/tests/operations/multiobjective/projection_tests.cpp b/tests/operations/multiobjective/projection_tests.cpp
@@ -94,12 +94,12 @@ TEST_F(projection_tests, translate_scaled_fitness_value) {
 
   // assert
   auto values = to_vector(population_.individuals());
-  EXPECT_NEAR(values[0], 1.75, 0.000001);
+  EXPECT_NEAR(values[0], 1.25, 0.000001);
   EXPECT_NEAR(values[1], 1.5, 0.000001);
-  EXPECT_NEAR(values[2], 2.25, 0.000001);
-  EXPECT_NEAR(values[3], 2.125, 0.000001);
-  EXPECT_NEAR(values[4], 3.049999, 0.000001);
-  EXPECT_NEAR(values[5], 3.024999, 0.000001);
+  EXPECT_NEAR(values[2], 2.75, 0.000001);
+  EXPECT_NEAR(values[3], 2.875, 0.000001);
+  EXPECT_NEAR(values[4], 3.95, 0.000001);
+  EXPECT_NEAR(values[5], 3.975, 0.000001);
 }
 
 TEST_F(projection_tests, truncate_ranking_scaled_fitness_value) {
@@ -130,12 +130,12 @@ TEST_F(projection_tests, truncate_density_scaled_fitness_value) {
 
   // assert
   auto values = to_vector(population_.individuals());
-  EXPECT_NEAR(values[0], 0.75, 0.0001);
+  EXPECT_NEAR(values[0], 0.25, 0.0001);
   EXPECT_NEAR(values[1], 0.5, 0.0001);
-  EXPECT_NEAR(values[2], 0.25, 0.0001);
-  EXPECT_NEAR(values[3], 0.125, 0.0001);
-  EXPECT_NEAR(values[4], 0.05, 0.0001);
-  EXPECT_NEAR(values[5], 0.025, 0.0001);
+  EXPECT_NEAR(values[2], 0.75, 0.0001);
+  EXPECT_NEAR(values[3], 0.875, 0.0001);
+  EXPECT_NEAR(values[4], 0.95, 0.0001);
+  EXPECT_NEAR(values[5], 0.975, 0.0001);
 }
 
 TEST_F(projection_tests, alternate_ranking_scaled_fitness_value) {
@@ -167,12 +167,12 @@ TEST_F(projection_tests, alternate_density_scaled_fitness_value) {
 
   // assert
   auto values = to_vector(population_.individuals());
-  EXPECT_NEAR(values[0], 0.75, 0.0001);
+  EXPECT_NEAR(values[0], 0.25, 0.0001);
   EXPECT_NEAR(values[1], 0.5, 0.0001);
-  EXPECT_NEAR(values[2], 0.25, 0.0001);
-  EXPECT_NEAR(values[3], 0.125, 0.0001);
-  EXPECT_NEAR(values[4], 0.05, 0.0001);
-  EXPECT_NEAR(values[5], 0.025, 0.0001);
+  EXPECT_NEAR(values[2], 0.75, 0.0001);
+  EXPECT_NEAR(values[3], 0.875, 0.0001);
+  EXPECT_NEAR(values[4], 0.95, 0.0001);
+  EXPECT_NEAR(values[5], 0.975, 0.0001);
 }
 
 TEST_F(projection_tests, custom_scaled_fitness_value) {
@@ -243,12 +243,12 @@ TEST_F(merge_tests, merge_scaled_fitness_value) {
   EXPECT_EQ(std::get<0>(values[4]), 3);
   EXPECT_EQ(std::get<0>(values[5]), 3);
 
-  EXPECT_NEAR(std::get<1>(values[0]), 0.75, 0.000001);
+  EXPECT_NEAR(std::get<1>(values[0]), 0.25, 0.000001);
   EXPECT_NEAR(std::get<1>(values[1]), 0.5, 0.000001);
-  EXPECT_NEAR(std::get<1>(values[2]), 0.25, 0.000001);
-  EXPECT_NEAR(std::get<1>(values[3]), 0.125, 0.000001);
-  EXPECT_NEAR(std::get<1>(values[4]), 0.05, 0.000001);
-  EXPECT_NEAR(std::get<1>(values[5]), 0.025, 0.000001);
+  EXPECT_NEAR(std::get<1>(values[2]), 0.75, 0.000001);
+  EXPECT_NEAR(std::get<1>(values[3]), 0.875, 0.000001);
+  EXPECT_NEAR(std::get<1>(values[4]), 0.95, 0.000001);
+  EXPECT_NEAR(std::get<1>(values[5]), 0.975, 0.000001);
 }
 
 } // namespace tests::projection