refactored integral histogram

.ci/docker/lint.Dockerfile

@@ -18,13 +18,15 @@ RUN wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | tee /etc/apt/trusted.
 
 FROM base AS deploy
 
-RUN echo deb http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-19 main \
+ARG clang_format_VERSION 19
+
+RUN echo deb http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-${clang_format_VERSION} main \
 >/etc/apt/sources.list.d/llvm.list
 
 COPY --from=tools /etc/apt/trusted.gpg.d/apt.llvm.org.asc /etc/apt/trusted.gpg.d/apt.llvm.org.asc
 
 RUN --mount=type=cache,target=/var/cache/apt \
 apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
 --no-install-recommends --no-install-suggests \
-clang-format-19 \
+clang-format-${clang_format_VERSION} \
 fd-find

.clang-format

@@ -95,7 +95,7 @@ SpacesInParentheses: false
 SpacesInSquareBrackets: false
 SpaceAfterTemplateKeyword: false
 FixNamespaceComments: true
-Standard:           c++17
+Standard:           c++20
 TabWidth:        4
 UseTab:          Never
 ...

.github/workflows/linux.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   lint:
     runs-on: ubuntu-24.04
-    container: sergiud/hogpp:lint
+    container: sergiud/hogpp:lint-18
     defaults:
       run:
         shell: bash -e -o pipefail {0}
@@ -17,12 +17,11 @@ jobs:
 
       - name: Check code style
         run: |
-          fdfind -g '*.[ch]pp' -x clang-format-19 --dry-run --Werror
+          fdfind -g '*.[ch]pp' -x clang-format-18 --dry-run --Werror
 
   build-native:
     name: ${{matrix.os}}-GCC-${{matrix.build_type}}
     runs-on: ${{matrix.os}}
-    needs: lint
     defaults:
       run:
         shell: bash

.gitlab-ci.yml

@@ -255,11 +255,11 @@ lint:pypy3.10:
   needs: []
 
 lint:cpp:
-  image: sergiud/hogpp:lint
+  image: sergiud/hogpp:lint-18
   stage: test
   allow_failure: true
   script:
-    - fdfind -g '*.[ch]pp' -x clang-format-19 --dry-run --Werror
+    - fdfind -g '*.[ch]pp' -x clang-format-18 --dry-run --Werror
   needs: []
 
 build:bookworm:

CMakeLists.txt

@@ -84,6 +84,7 @@ endif (MSVC AND MSVC_VERSION GREATER_EQUAL 1930)
 check_cxx_symbol_exists (std::execution::par execution HAVE_EXECUTION)
 
 if (WIN32)
+  add_compile_definitions (NOMINMAX)
   add_compile_definitions (WIN32_LEAN_AND_MEAN)
 endif (WIN32)
 
@@ -100,7 +101,7 @@ target_include_directories (hogpp INTERFACE
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
 )
 
-target_compile_features (hogpp INTERFACE cxx_std_17)
+target_compile_features (hogpp INTERFACE cxx_std_20)
 target_link_libraries (hogpp INTERFACE
   Eigen3::Eigen
   fmt::fmt
@@ -110,7 +111,6 @@ if (pybind11_FOUND AND Python_Development.Module_FOUND)
   add_library (python_type_caster STATIC
     python/type_caster/bounds.cpp
     python/type_caster/bounds.hpp
-    python/type_caster/cartesianproduct.hpp
     python/type_caster/stride.hpp
     python/type_caster/tensor.hpp
     python/type_caster/typesequence.hpp
@@ -124,7 +124,6 @@ if (pybind11_FOUND AND Python_Development.Module_FOUND)
     target_link_libraries (python_type_caster PUBLIC opencv_core)
   endif (OpenCV_FOUND)
 
-  target_compile_features (python_type_caster PUBLIC cxx_std_17)
   target_link_libraries (python_type_caster PUBLIC
     Eigen3::Eigen
     hogpp::hogpp
@@ -188,6 +187,18 @@ endif (pybind11_FOUND AND Python_Development.Module_FOUND)
 
 if (BUILD_TESTING)
   if (Boost_unit_test_framework_FOUND)
+    add_executable (test_integral_histogram
+      tests/cpp/test_integral_histogram.cpp
+    )
+    target_link_libraries (test_integral_histogram PRIVATE
+      Boost::unit_test_framework
+      Eigen3::Eigen
+      hogpp::hogpp
+    )
+
+    add_test (NAME integral_histogram_full COMMAND test_integral_histogram -t full)
+    add_test (NAME integral_histogram_sub COMMAND test_integral_histogram -t sub)
+
     add_executable (test_binning tests/cpp/test_binning.cpp)
     target_link_libraries (test_binning PRIVATE hogpp::hogpp
       Boost::unit_test_framework)

docs/build.rst

@@ -4,7 +4,7 @@ Compiling from Source
 Requirements
 ------------
 
--  C++17 compiler
+-  C++20 compiler
 -  `CMake <https://gitlab.kitware.com/cmake/cmake>`__ 3.18
 -  `Eigen <https://gitlab.com/libeigen/eigen>`__ 3.3.7
 -  `fmt <https://github.com/fmtlib/fmt>`__ 6.0

python/type_caster/cartesianproduct.hpp → include/hogpp/cartesianproduct.hpp

@@ -17,45 +17,49 @@
 // limitations under the License.
 //
 
-#ifndef PYTHON_TYPE_CASTER_CARTESIANPRODUCT_HPP
-#define PYTHON_TYPE_CASTER_CARTESIANPRODUCT_HPP
+#ifndef HOGPP_CARTESIANPRODUCT_HPP
+#define HOGPP_CARTESIANPRODUCT_HPP
 
+#include <concepts>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 
-template<class... Sizes, class Function, class... Loops>
+namespace hogpp {
+
+template<std::integral... Sizes, class Body, std::integral... Loops>
 constexpr void cartesianProduct(
-    const std::tuple<Sizes...>& /*s*/, const std::tuple<Loops...>& l,
-    Function&& func,
-    std::index_sequence<> /*unused*/) noexcept(noexcept(func(l)))
+    [[maybe_unused]] const std::tuple<Sizes...>& s,
+    const std::tuple<Loops...>& l, Body&& body,
+    std::index_sequence<> /*unused*/) noexcept(noexcept(body(l)))
 {
-    func(l);
+    body(l);
 }
 
-template<class... Sizes, class Function, class... Loops, std::size_t Index,
-         std::size_t... Indices>
+template<std::integral... Sizes, class Body, std::integral... Loops,
+         std::size_t Index, std::size_t... Indices>
 constexpr void cartesianProduct(
-    const std::tuple<Sizes...>& s, const std::tuple<Loops...>& l,
-    Function&& func,
+    const std::tuple<Sizes...>& s, const std::tuple<Loops...>& l, Body&& body,
     std::index_sequence<
         Index,
-        Indices...> /*unused*/) noexcept(noexcept(func(std::declval<std::tuple<Sizes...>>())))
+        Indices...> /*unused*/) noexcept(noexcept(body(std::declval<std::tuple<Sizes...>>())))
 {
     for (auto i = 0; i < std::get<Index>(s); ++i) {
         cartesianProduct(s, std::tuple_cat(l, std::make_tuple(i)),
-                         std::forward<Function>(func),
+                         std::forward<Body>(body),
                          std::index_sequence<Indices...>{});
     }
 }
 
-template<class... Sizes, class Function>
-constexpr void
-cartesianProduct(const std::tuple<Sizes...>& s, Function&& func) noexcept(
-    noexcept(func(std::declval<std::tuple<Sizes...>>())))
+template<std::integral... Sizes, class Body>
+constexpr void cartesianProduct(
+    const std::tuple<Sizes...>& s,
+    Body&& body) noexcept(noexcept(body(std::declval<std::tuple<Sizes...>>())))
 {
-    cartesianProduct(s, std::tuple<>{}, std::forward<Function>(func),
+    cartesianProduct(s, std::tuple<>{}, std::forward<Body>(body),
                      std::index_sequence_for<Sizes...>{});
 }
 
-#endif // PYTHON_TYPE_CASTER_CARTESIANPRODUCT_HPP
+} // namespace hogpp
+
+#endif // HOGPP_CARTESIANPRODUCT_HPP

include/hogpp/constants.hpp

@@ -20,18 +20,18 @@
 #ifndef HOGPP_CONSTANTS_HPP
 #define HOGPP_CONSTANTS_HPP
 
+#include <numbers>
+
 namespace hogpp::constants {
 
 template<class T>
-inline constexpr T pi = T(3.1415926535897932384626433832795028841971693993751);
+inline constexpr T pi = std::numbers::pi_v<T>;
 
 template<class T>
-inline constexpr T two_pi =
-    T(6.28318530717958623199592693708837032318115234375);
+inline constexpr T two_pi = 2 * pi<T>;
 
 template<class T>
-inline constexpr T half_pi =
-    T(1.5707963267948965579989817342720925807952880859375);
+inline constexpr T half_pi = pi<T> / 2;
 
 } // namespace hogpp::constants