From f8782e22462127e81f92256c181e918f2c19a619 Mon Sep 17 00:00:00 2001
From: KRM7 <70973547+KRM7@users.noreply.github.com>
Date: Tue, 15 Aug 2023 18:46:41 +0200
Subject: [PATCH] Create 10_fp_context.cpp

---
 examples/10_fp_context.cpp | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 examples/10_fp_context.cpp

diff --git a/examples/10_fp_context.cpp b/examples/10_fp_context.cpp
new file mode 100644
index 00000000..69a0bfdf
--- /dev/null
+++ b/examples/10_fp_context.cpp
@@ -0,0 +1,37 @@
+/* Example showing how to change the tolerances used for floating-point comparisons in the GA. */
+
+#include "gapp.hpp" // include everything
+#include <iostream>
+#include <cmath>
+
+using namespace gapp;
+
+class SinX : public FitnessFunction<RealGene, 1>
+{
+    FitnessVector invoke(const Chromosome<RealGene>& x) const override { return { std::sin(x[0]) }; }
+};
+
+int main()
+{
+    std::cout << "The default absolute tolerance used is " << math::Tolerances::abs() << "\n";
+    std::cout << "The default relative tolerance around 1.0 is " << math::Tolerances::rel(1.0) << "\n";
+
+    {
+        auto solutions = RCGA{}.solve(SinX{}, Bounds{ 0.0, 3.14 });
+        std::cout << "The maximum of sin(x) in [0.0, 3.14] is at x = " << solutions[0].chromosome[0] << "\n";
+    }
+
+    {
+        math::ScopedTolerances _(/* abs = */ 0.1, /* rel = */ 0.1);
+
+        auto solutions = RCGA{}.solve(SinX{}, Bounds{ 0.0, 3.14 });
+        std::cout << "The maximum of sin(x) in [0.0, 3.14] is at x = " << solutions[0].chromosome[0] << "\n";
+    }
+
+    {
+        math::ScopedTolerances _(/* abs = */ 0.0, /* rel = */ 0.0);
+
+        auto solutions = RCGA{}.solve(SinX{}, Bounds{ 0.0, 3.14 });
+        std::cout << "The maximum of sin(x) in [0.0, 3.14] is at x = " << solutions[0].chromosome[0] << "\n";
+    }
+}