required standard reduced from C++20 to C++17

.github/workflows/ubuntu-unit.yml

@@ -30,7 +30,7 @@ jobs:
           - CC: gcc-13
             CXX: g++-13
             compiler: gcc-13 g++-13
-          - CC: clang-12 # -> error: call to consteval function 'std::chrono::hh_mm_ss::_S_fractional_width' is not a constant expression
+          - CC: clang-12
             CXX: clang++-12
             compiler: clang-12 libomp-12-dev
           - CC: clang-13

CHANGELOG.md

@@ -19,6 +19,10 @@ This changelog contains a non-exhaustive list of new features and notable bug-fi
 ## API changes
 * N/A
 
+## Dependency updates:
+* Required C++ standard is reduced from C++20 to C++17 as it was causing `call to consteval function 'std::chrono::hh_mm_ss::_S_fractional_width' is not a constant expression` error for clang versions older than clang-15.
+* std::execution-based parallelisation changed with OpenMP.
+
 
 <br/><br/>
 # DTWC v0.0.3

CMakeLists.txt

@@ -29,7 +29,7 @@ add_library(project_warnings INTERFACE)
 
 # Link this 'library' to set the c++ standard / compile-time options requested
 add_library(project_options INTERFACE)
-target_compile_features(project_options INTERFACE cxx_std_20)
+target_compile_features(project_options INTERFACE cxx_std_17)
 
 enable_testing()
 

cmake/Dependencies.cmake

@@ -60,7 +60,7 @@ function(dtwc_setup_dependencies)
     SYSTEM
     EXCLUDE_FROM_ALL
     OPTIONS
-    "ZLIB OFF" "FAST_BUILD ON" "BUILD_TESTING OFF" "BUILD_EXAMPLES OFF" "CMAKE_CXX_STANDARD 20")
+    "ZLIB OFF" "FAST_BUILD ON" "BUILD_TESTING OFF" "BUILD_EXAMPLES OFF")
   endif()
 
 endfunction()

cmake/StandardProjectSettings.cmake

@@ -21,7 +21,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 # when compiling with PCH enabled
 set(CMAKE_CXX_EXTENSIONS OFF)
 # Only set the cxx_standard if it is not set by someone else
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_VERBOSE_MAKEFILE ON)
 
 

dtwc/CMakeLists.txt

@@ -51,4 +51,4 @@ if(OpenMP_CXX_FOUND)
   target_link_libraries(dtwc++ PUBLIC OpenMP::OpenMP_CXX)
 endif()
 
-set_property(TARGET dtwc++ PROPERTY CXX_STANDARD 20)
+set_property(TARGET dtwc++ PROPERTY CXX_STANDARD 17)

dtwc/Data.hpp

@@ -34,7 +34,7 @@ struct Data
     assert(p_vec_new.size() == p_names_new.size());
     p_vec = std::move(p_vec_new);
     p_names = std::move(p_names_new);
-    Nb = std::ssize(p_vec);
+    Nb = static_cast<int>(p_vec.size());
   }
 };
 

dtwc/DataLoader.hpp

@@ -79,7 +79,7 @@ class DataLoader
     else
       std::tie(d.p_vec, d.p_names) = load_batch_file<data_t>(data_path, Ndata, verbose > 0, start_row, start_col, delimiter);
 
-    d.Nb = std::ssize(d.p_vec);
+    d.Nb = static_cast<int>(d.p_vec.size());
     return d;
   }
 };

dtwc/mip.cpp

@@ -28,7 +28,8 @@
 
 namespace dtwc {
 
-void extract_solution(Problem &prob, auto &solution)
+template <typename T>
+void extract_solution(Problem &prob, const T &solution)
 {
   prob.clear_clusters();
   const auto Nb = prob.data.size();

dtwc/types/element_types.hpp

@@ -59,15 +59,17 @@ struct CompElementValuesAndIndices
 
 struct RowMajor
 {
-  bool operator()(const auto &c1, const auto &c2) const
+  template <typename T>
+  bool operator()(const T &c1, const T &c2) const
   {
     return (c1.col < c2.col) || (c1.col == c2.col && c1.row < c2.row);
   }
 };
 
 struct ColumnMajor
 {
-  bool operator()(const auto &c1, const auto &c2) const
+  template <typename T>
+  bool operator()(const T &c1, const T &c2) const
   {
     return (c1.row < c2.row) || (c1.row == c2.row && c1.col < c2.col);
   }

dtwc/warping.hpp

@@ -22,7 +22,7 @@ namespace dtwc {
 template <typename data_t>
 data_t dtwFull(const std::vector<data_t> &x, const std::vector<data_t> &y)
 {
-  thread_local VecMatrix<data_t> C(std::ssize(x), std::ssize(y)); //
+  thread_local VecMatrix<data_t> C(x.size(), y.size()); //
   constexpr data_t maxValue = std::numeric_limits<data_t>::max();
 
   if (&x == &y) return 0; // If they are the same data then distance is 0.