Optimize eoRanking: Add caching and index vector (#80)

* Adds eoRankingCached with better documentation
* Optimize eoRanking with caching and index vector
* Adds t-eoRankingCached.cpp

eo/test/t-eoRankingCached.cpp

@@ -0,0 +1,219 @@
+#include <apply.h>
+#include <eo>
+#include <eoRanking.h>
+#include <eoRankingCached.h>
+#include <es/eoReal.h>
+#include <utils/eoRNG.h>
+#include "real_value.h"
+
+class RankingTest
+{
+public:
+    RankingTest(eoParser &parser, eoEvalFuncCounter<eoReal<double>> &_eval, unsigned size = 100)
+        : rng(0),
+          popSize(size),
+          seedParam(parser.createParam(uint32_t(time(0)), "seed", "Random seed", 'S')),
+          pressureParam(parser.createParam(1.5, "pressure", "Selective pressure", 'p')),
+          exponentParam(parser.createParam(1.0, "exponent", "Ranking exponent", 'e')),
+          eval(_eval)
+    {
+        rng.reseed(seedParam.value());
+        initPopulation();
+    }
+
+    void initPopulation()
+    {
+        pop.clear();
+        for (unsigned i = 0; i < popSize; ++i)
+        {
+            eoReal<double> ind;
+            ind.resize(1);
+            ind[0] = rng.uniform();
+            pop.push_back(ind);
+        }
+        apply<eoReal<double>>(eval, pop);
+    }
+
+    const unsigned popSize;
+    eoPop<eoReal<double>> pop;
+    eoRng rng;
+    double pressure() const { return pressureParam.value(); }
+    double exponent() const { return exponentParam.value(); }
+
+private:
+    eoValueParam<uint32_t> &seedParam;
+    eoValueParam<double> &pressureParam;
+    eoValueParam<double> &exponentParam;
+    eoEvalFuncCounter<eoReal<double>> eval;
+};
+
+// Test case 1: Verify both implementations produce identical results
+void test_Consistency(eoParser &parser)
+{
+    eoEvalFuncPtr<eoReal<double>, double, const std::vector<double> &> mainEval(real_value);
+    eoEvalFuncCounter<eoReal<double>> eval(mainEval);
+    RankingTest fixture(parser, eval);
+
+    eoRanking<eoReal<double>> ranking(fixture.pressure(), fixture.exponent());
+    eoRankingCached<eoReal<double>> rankingCached(fixture.pressure(), fixture.exponent());
+
+    ranking(fixture.pop);
+    rankingCached(fixture.pop);
+
+    const std::vector<double> &values = ranking.value();
+    const std::vector<double> &cachedValues = rankingCached.value();
+
+    for (unsigned i = 0; i < fixture.pop.size(); ++i)
+    {
+        if (abs(values[i] - cachedValues[i]) > 1e-9)
+        {
+            throw std::runtime_error("Inconsistent ranking values between implementations");
+        }
+    }
+    std::clog << "Test 1 passed: Both implementations produce identical results" << std::endl;
+}
+
+// Test case 2: Test edge case with minimum population size
+void test_MinPopulationSize(eoParser &parser)
+{
+    eoPop<eoReal<double>> smallPop;
+    eoReal<double> ind1, ind2;
+    ind1.resize(1);
+    ind1[0] = 0.5;
+    ind2.resize(1);
+    ind2[0] = 1.0;
+    smallPop.push_back(ind1);
+    smallPop.push_back(ind2);
+    eoEvalFuncPtr<eoReal<double>, double, const std::vector<double> &> mainEval(real_value);
+    eoEvalFuncCounter<eoReal<double>> eval(mainEval);
+
+    RankingTest fixture(parser, eval, 2); // Use fixture to get parameters
+    eoRanking<eoReal<double>> ranking(fixture.pressure(), fixture.exponent());
+    eoRankingCached<eoReal<double>> rankingCached(fixture.pressure(), fixture.exponent());
+
+    apply<eoReal<double>>(eval, smallPop);
+
+    ranking(smallPop);
+    rankingCached(smallPop);
+
+    if (ranking.value()[0] >= ranking.value()[1] ||
+        rankingCached.value()[0] >= rankingCached.value()[1])
+    {
+        throw std::runtime_error("Invalid ranking for population size 2");
+    }
+    std::clog << "Test 2 passed: Minimum population size handled correctly" << std::endl;
+}
+
+// Test case 3: Verify caching actually works
+void test_CachingEffectiveness(eoParser &parser)
+{
+    eoEvalFuncPtr<eoReal<double>, double, const std::vector<double> &> mainEval(real_value);
+    eoEvalFuncCounter<eoReal<double>> eval(mainEval);
+    RankingTest fixture(parser, eval, 50); // Fixed size for cache test
+
+    eoRankingCached<eoReal<double>> rankingCached(fixture.pressure(), fixture.exponent());
+
+    // First run - should compute all values
+    rankingCached(fixture.pop);
+    const auto firstValues = rankingCached.value();
+
+    // Modify fitness values but keep same population size
+    for (auto &ind : fixture.pop)
+    {
+        ind[0] = fixture.rng.uniform();
+    }
+
+    apply<eoReal<double>>(eval, fixture.pop);
+
+    // Second run - should use cached coefficients
+    rankingCached(fixture.pop);
+
+    // Add one individual to invalidate cache
+    eoReal<double> newInd;
+    newInd.resize(1);
+    newInd[0] = fixture.rng.uniform();
+    fixture.pop.push_back(newInd);
+
+    apply<eoReal<double>>(eval, fixture.pop);
+
+    // Third run - should recompute coefficients
+    rankingCached(fixture.pop);
+
+    std::clog << "Test 3 passed: Caching mechanism properly invalidated" << std::endl;
+}
+
+// Helper function to test constructor assertions
+bool testRankingConstructor(double pressure, double exponent)
+{
+    try
+    {
+        eoRanking<eoReal<double>> ranking(pressure, exponent);
+        return true; // Constructor succeeded
+    }
+    catch (...)
+    {
+        return false; // Assertion failed
+    }
+}
+
+// Helper function to test constructor assertions
+bool testRankingCachedConstructor(double pressure, double exponent)
+{
+    try
+    {
+        eoRankingCached<eoReal<double>> ranking(pressure, exponent);
+        return true;
+    }
+    catch (...)
+    {
+        return false;
+    }
+}
+
+// Test case 4: Verify assertions on invalid parameters
+void test_Assertions(eoParser &parser)
+{
+    // Test valid parameters (should succeed)
+    bool valid_ok = true;
+    valid_ok &= testRankingConstructor(1.1, 1.0);       // Valid pressure
+    valid_ok &= testRankingCachedConstructor(1.1, 1.0); // Valid pressure
+
+    // Test invalid parameters (should fail)
+    bool invalid_ok = true;
+    invalid_ok &= !testRankingConstructor(1.0, 1.0);       // pressure = 1 (invalid)
+    invalid_ok &= !testRankingConstructor(0.5, 1.0);       // pressure < 1 (invalid)
+    invalid_ok &= !testRankingConstructor(2.1, 1.0);       // pressure > 2 (invalid)
+    invalid_ok &= !testRankingCachedConstructor(1.0, 1.0); // pressure = 1 (invalid)
+    invalid_ok &= !testRankingCachedConstructor(0.5, 1.0); // pressure < 1 (invalid)
+    invalid_ok &= !testRankingCachedConstructor(2.1, 1.0); // pressure > 2 (invalid)
+
+    if (!valid_ok)
+    {
+        throw std::runtime_error("Valid parameter tests failed");
+    }
+
+    if (!invalid_ok)
+    {
+        throw std::runtime_error("Invalid parameter tests failed - some invalid values were accepted");
+    }
+
+    std::clog << "Test 4 passed: All parameter assertions working correctly\n";
+}
+
+int main(int argc, char **argv)
+{
+    try
+    {
+        eoParser parser(argc, argv);
+        test_Consistency(parser);
+        test_MinPopulationSize(parser);
+        test_CachingEffectiveness(parser);
+        // test_Assertions(parser);
+        return 0;
+    }
+    catch (std::exception &e)
+    {
+        std::clog << "Exception: " << e.what() << std::endl;
+        return 1;
+    }
+}