Implemented data-driven testing for dist, related fixes and docs

.github/workflows/ci.yml

@@ -21,6 +21,8 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          submodules: true
       - name: Install dependencies
         run: ./helper.py -d
       - name: Build

.github/workflows/codeql.yml

@@ -27,6 +27,8 @@ jobs:
     steps:
     - name: Checkout repository
       uses: actions/checkout@v4
+      with:
+        submodules: true
 
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3

.gitmodules

@@ -0,0 +1,8 @@
+[submodule "tests/deps/toml++"]
+	path = tests/deps/toml++
+	url = [email protected]:marzer/tomlplusplus
+	shallow = true
+[submodule "tests/test_data"]
+	path = tests/test_data
+	url = [email protected]:ALFI-library/test_data
+	shallow = true

ALFI/ALFI/dist.h

@@ -1,9 +1,10 @@
 #pragma once
 
-#include "config.h"
-
 #include <cmath>
 
+#include "config.h"
+#include "util/points.h"
+
 namespace alfi::dist {
 	enum class Type {
 		GENERAL,
@@ -20,30 +21,6 @@ namespace alfi::dist {
 		ERF_STRETCHED,
 	};
 
-	template <typename Number = DefaultNumber>
-	void stretch(auto& points, Number a, Number b) {
-		if (points.empty()) {
-			return;
-		}
-
-		if (points.size() == 1 || points.front() == points.back()) {
-			std::fill(points.begin(), points.end(), (a + b) / 2);
-			return;
-		}
-
-		const Number& min = points.front();
-		const Number& max = points.back();
-		const Number mid = (a + b) / 2;
-		const Number scale = (b - a) / (max - min);
-
-		for (SizeT i = 1; i < points.size() - 1; ++i) {
-			points[i] = mid + scale * (points[i] - mid);
-		}
-
-		points.front() = a;
-		points.back() = b;
-	}
-
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> uniform(SizeT n, Number a, Number b) {
 		if (n == 1)
@@ -69,9 +46,7 @@ namespace alfi::dist {
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> chebyshev_stretched(SizeT n, Number a, Number b) {
-		Container<Number> points = chebyshev(n, a, b);
-		stretch(points, a, b);
-		return points;
+		return points::stretched(chebyshev(n, a, b), a, b);
 	}
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
@@ -90,9 +65,7 @@ namespace alfi::dist {
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> chebyshev_ellipse_stretched(SizeT n, Number a, Number b, Number ratio) {
-		Container<Number> points = chebyshev_ellipse(n, a, b, ratio);
-		stretch(points, a, b);
-		return points;
+		return points::stretched(chebyshev_ellipse(n, a, b, ratio), a, b);
 	}
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
@@ -121,14 +94,35 @@ namespace alfi::dist {
 		return points;
 	}
 
+	/**
+		@brief Generates a distribution of \p n points on the interval `(a, b)` using the sigmoid function.
+
+		The following transform function \f(f\f):
+		\f[f(x) = \frac{1}{1 + e^{-steepness \cdot x}}\f]
+		is applied to `n` points uniformly distributed on the interval `(-1, 1)`, mapping them onto the `(0, 1)` interval.\n
+		The resulting points are then linearly mapped to the target interval `(a, b)`.
+
+		The slope of the transform function \f(f\f) at `x = 0` is determined by \p steepness and is given by:
+		\f[
+		\left. \dv{f}{x} \right\vert_{x=0} = \frac14 \cdot steepness
+		\f]
+
+		@note Extreme points don't lie on the interval `(a, b)` boundaries.
+
+		@param n number of points
+		@param a left boundary of the interval
+		@param b right boundary of the interval
+		@param steepness determines the slope of the transform function at `x = 0`
+		@return a container with \p n points distributed on the interval `(a, b)` according to the transform function
+	*/
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> sigmoid(SizeT n, Number a, Number b, Number steepness) {
 		if (n == 1)
 			return {(a+b)/2};
 		Container<Number> points(n);
 		for (SizeT i = 0; i < n; ++i) {
-			const Number x = static_cast<Number>(i) / (static_cast<Number>(n) - 1);
-			const Number sigmoidValue = 1.0 / (1.0 + exp(-steepness * (x - 0.5)));
+			const Number x = 2 * static_cast<Number>(i) / (static_cast<Number>(n) - 1) - 1;
+			const Number sigmoidValue = 1 / (1 + exp(-steepness * x));
 			points[i] = a + (b - a) * sigmoidValue;
 		}
 		return points;
@@ -141,18 +135,39 @@ namespace alfi::dist {
 		if (n == 1)
 			return {(a+b)/2};
 		Container<Number> points(n);
-		const Number stretch_factor = 1 - 2 / (1 + std::exp(0.5 * steepness));
+		const Number stretch_factor = 1 - 2 / (1 + std::exp(steepness));
 		for (SizeT i = 1; i < n - 1; ++i) {
-			const Number x = static_cast<double>(i) / (static_cast<Number>(n) - 1);
-			const Number sigmoid = 1.0 / (1.0 + std::exp(-steepness * (x - 0.5)));
-			const Number stretched = (sigmoid - 1.0 / (1.0 + std::exp(0.5 * steepness))) / stretch_factor;
+			const Number x = 2 * static_cast<double>(i) / (static_cast<Number>(n) - 1) - 1;
+			const Number sigmoid = 1 / (1 + std::exp(-steepness * x));
+			const Number stretched = (sigmoid - 1 / (1 + std::exp(steepness))) / stretch_factor;
 			points[i] = a + (b - a) * stretched;
 		}
 		points[0] = a;
 		points[n-1] = b;
 		return points;
 	}
 
+	/**
+		@brief Generates a distribution of \p n points on the interval `(a, b)` using the error function.
+
+		The following transform function \f(f\f):
+		\f[f(x) = \operatorname{erf}(steepness \cdot x)\f]
+		is applied to `n` points uniformly distributed on the interval `(-1, 1)`, mapping them onto the same interval.\n
+		The resulting points are then linearly mapped to the target interval `(a, b)`.
+
+		The slope of the transform function \f(f\f) at `x = 0` is determined by \p steepness and is given by:
+		\f[
+		\left. \dv{f}{x} \right\vert_{x=0} = \frac2\pi \cdot steepness
+		\f]
+
+		@note Extreme points don't lie on the interval `(a, b)` boundaries.
+
+		@param n number of points
+		@param a left boundary of the interval
+		@param b right boundary of the interval
+		@param steepness determines the slope of the transform function at `x = 0`
+		@return a container with \p n points distributed on the interval `(a, b)` according to the transform function
+	*/
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> erf(SizeT n, Number a, Number b, Number steepness) {
 		if (n == 0)
@@ -161,22 +176,20 @@ namespace alfi::dist {
 			return {(a+b)/2};
 		Container<Number> points(n);
 		for (SizeT i = 0; i < n; ++i) {
-			const Number x = static_cast<Number>(i) / (static_cast<Number>(n) - 1);
-			const Number erf_value = std::erf(steepness * (x - 0.5));
+			const Number x = 2 * static_cast<Number>(i) / (static_cast<Number>(n) - 1) - 1;
+			const Number erf_value = std::erf(steepness * x);
 			points[i] = a + (b - a) * (1 + erf_value) / 2;
 		}
 		return points;
 	}
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
 	Container<Number> erf_stretched(SizeT n, Number a, Number b, Number steepness) {
-		Container<Number> points = erf(n, a, b, steepness);
-		stretch(points, a, b);
-		return points;
+		return points::stretched(erf(n, a, b, steepness), a, b);
 	}
 
 	template <typename Number = DefaultNumber, template <typename> class Container = DefaultContainer>
-	Container<Number> of_type(Type type, SizeT n, Number a, Number b, Number parameter = 0) {
+	Container<Number> of_type(Type type, SizeT n, Number a, Number b, Number parameter = NAN) {
 		switch (type) {
 		case Type::CHEBYSHEV:
 			return chebyshev(n, a, b);

ALFI/ALFI/util/points.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include "../config.h"
+
+namespace alfi::points {
+	template <typename Number = DefaultNumber>
+	void lin_map(auto& points, Number a, Number b, Number c, Number d) {
+		const auto mid1 = (a + b) / 2;
+		const auto mid2 = (c + d) / 2;
+		const auto scale = (d - c) / (b - a);
+		for (auto& point : points) {
+			point = mid2 + scale * (point - mid1);
+		}
+	}
+
+	template <typename Number = DefaultNumber>
+	auto lin_mapped(const auto& points, Number a, Number b, Number c, Number d) {
+		auto mapped_points = points;
+		lin_map(mapped_points, a, b, c, d);
+		return mapped_points;
+	}
+
+	template <typename Number = DefaultNumber>
+	void stretch(auto& points, Number a, Number b) {
+		if (points.empty()) {
+			return;
+		}
+		if (points.size() == 1 || points.front() == points.back()) {
+			std::fill(points.begin(), points.end(), (a + b) / 2);
+			return;
+		}
+		lin_map(points, points.front(), points.back(), a, b);
+		points.front() = a;
+		points.back() = b;
+	}
+
+	template <typename Number = DefaultNumber>
+	auto stretched(const auto& points, Number a, Number b) {
+		auto stretched_points = points;
+		stretch(stretched_points, a, b);
+		return stretched_points;
+	}
+}

helper.py

@@ -15,6 +15,7 @@
 dependencies = [
 	'build-essential',
 	'cmake',
+	'git',
 	'libgnuplot-iostream-dev',
 	'libgtest-dev',
 	'libqcustomplot-dev',
@@ -48,6 +49,7 @@ def execute_command(command):
 if args.deps:
 	execute_command(['sudo', 'apt', 'update'])
 	execute_command(['sudo', 'apt', 'install', '-y'] + dependencies)
+	execute_command(['git', 'submodule', 'update', '--init'])
 if args.build:
 	execute_command(['cmake', '-DCMAKE_BUILD_TYPE=' + args.profile, '-B', profile_dir])
 	execute_command(['cmake', '--build', profile_dir, '-j', str(os.cpu_count())])

tests/CMakeLists.txt

@@ -1,13 +1,17 @@
 set(CMAKE_CXX_STANDARD 23)
 
 find_package(GTest REQUIRED)
+add_subdirectory(deps/toml++)
+
+set(TEST_DATA_DIR "${CMAKE_CURRENT_LIST_DIR}/test_data")
 
 macro(add_test_executable test_name)
 	add_executable(${test_name} ${ARGN} test_utils.h)
 	target_include_directories(${test_name} PRIVATE ${GTEST_INCLUDE_DIRS})
-	target_link_libraries(${test_name} PRIVATE ALFI GTest::GTest GTest::Main)
+	target_link_libraries(${test_name} PRIVATE ALFI GTest::GTest GTest::Main tomlplusplus::tomlplusplus)
 	target_compile_options(${test_name} PRIVATE -fsanitize=address,leak,undefined)
 	target_link_options(${test_name} PRIVATE -fsanitize=address,leak,undefined)
+	target_compile_definitions(${test_name} PRIVATE TEST_DATA_DIR="${TEST_DATA_DIR}")
 	add_test(NAME ${test_name} COMMAND ${test_name} --gtest_color=yes)
 endmacro()