Improved continuous integration testing

.github/workflows/ghaction.yml

@@ -1,16 +1,20 @@
-name: stdBLAS
+name: build/test
 
 on: [push, pull_request]
 
-env:
-  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
-  BUILD_TYPE: RelWithDebInfo
-
 jobs:
   osmatrix: 
     strategy:
+      # Don't cancel all other builds if one fails
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        # A full list of runners can be found here: 
+        # https://docs.github.com/en/actions/reference/runners/github-hosted-runners
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        build-type: [RelWithDebInfo]
+        cxx-standard: [17,20]
+        # In theory, we would test on older compilers such as gcc 7.5, clang 9, and vs 2019
+        # They are not installed on the runners by default, leaving this as a TODO item for now.
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -24,38 +28,28 @@ jobs:
       run: cmake -E make_directory mdspan-build stdblas-build
 
     - name: Configure mdspan
-      working-directory: mdspan-build
-      run: cmake -S $GITHUB_WORKSPACE/mdspan-src -B $GITHUB_WORKSPACE/mdspan-build -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DCMAKE_INSTALL_PREFIX=$GITHUB_WORKSPACE/mdspan-install
+      run: cmake -S mdspan-src -B mdspan-build -DMDSPAN_CXX_STANDARD=${{matrix.cxx-standard}} -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -DCMAKE_INSTALL_PREFIX=mdspan-install
 
     - name: Build mdspan
-      working-directory: mdspan-build
-      run: cmake --build $GITHUB_WORKSPACE/mdspan-build -j 3
+      run: cmake --build mdspan-build -j 3
 
     - name: Install mdspan
-      working-directory: mdspan-build
-      run: cmake --install $GITHUB_WORKSPACE/mdspan-build
+      run: cmake --install mdspan-build
 
-    - name: Check Out
+    - name: Check Out stdblas
       uses: actions/checkout@v4
       with:
         path: stdblas-src
 
     - name: Configure stdblas
-      shell: bash
-      working-directory: stdblas-build
-      run: cmake -S $GITHUB_WORKSPACE/stdblas-src -B $GITHUB_WORKSPACE/stdblas-build -Dmdspan_DIR=$GITHUB_WORKSPACE/mdspan-install/ -DLINALG_ENABLE_TESTS=On -DLINALG_ENABLE_EXAMPLES=On -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DCMAKE_INSTALL_PREFIX=$GITHUB_WORKSPACE/stdblas-install
+      run: cmake -S stdblas-src -B stdblas-build -Dmdspan_DIR=mdspan-install -DLINALG_CXX_STANDARD=${{matrix.cxx-standard}} -DLINALG_ENABLE_TESTS=On -DLINALG_ENABLE_EXAMPLES=On -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -DCMAKE_INSTALL_PREFIX=stdblas-install
 
     - name: Build stdblas
-      working-directory: stdblas-build
-      shell: bash
-      run: cmake --build $GITHUB_WORKSPACE/stdblas-build -j 3
+      run: cmake --build stdblas-build -j 3
 
     - name: Test stdblas
       working-directory: stdblas-build
-      shell: bash
       run: ctest --output-on-failure
 
     - name: Install stdblas
-      working-directory: stdblas-build
-      shell: bash
-      run: cmake --install $GITHUB_WORKSPACE/stdblas-build
+      run: cmake --install stdblas-build

include/experimental/__p1673_bits/linalg_execpolicy_mapper.hpp

@@ -105,12 +105,11 @@ auto execpolicy_mapper(T) { return impl::inline_exec_t(); }
 namespace impl {
 
 // std::remove_cvref_t is a C++20 feature.
-template<class T>
-using remove_cvref_t =
 #ifdef __cpp_lib_remove_cvref
-  std::remove_cvref_t<T>;
+using std::remove_cvref_t;
 #else
-  std::remove_const_t<std::remove_reference_t<decltype(policy)>>;
+template<class T>
+using remove_cvref_t = std::remove_const_t<std::remove_reference_t<T>>;
 #endif
 
 // This function is not to be specialized; that's why

include/experimental/__p1673_bits/proxy_reference.hpp

@@ -140,11 +140,7 @@ class proxy_reference : proxy_reference_base {
   P1673_PROXY_REFERENCE_ARITHMETIC_OPERATOR( / )
 
   friend auto abs(const derived_type& x) {
-    if constexpr (std::is_unsigned_v<value_type>) {
-      return value_type(static_cast<const this_type&>(x));
-    } else {
-      return abs(value_type(static_cast<const this_type&>(x)));
-    }
+    return impl::abs_if_needed(value_type(static_cast<const this_type&>(x)));
   }
 
   friend auto real(const derived_type& x) {

include/experimental/__p1673_bits/transposed.hpp

@@ -105,9 +105,14 @@ class layout_transpose {
       return nested_mapping_.required_span_size();
     }
 
-    template<class IndexType0, class IndexType1>
-      requires(std::is_convertible_v<IndexType0, index_type> &&
-               std::is_convertible_v<IndexType1, index_type>)
+    MDSPAN_TEMPLATE_REQUIRES(
+      class IndexType0,
+      class IndexType1,
+      /* requires */ (
+        std::is_convertible_v<IndexType0, index_type> &&
+        std::is_convertible_v<IndexType1, index_type>
+      )
+    )
     index_type operator() (IndexType0 i, IndexType1 j) const
     {
       return nested_mapping_(j, i);

tests/native/transposed.cpp

@@ -200,8 +200,8 @@ namespace {
     }
   }
 
-  template<size_t PaddingValue>
-  void test_transposed_layout_left_padded(auto runtime_padding_value)
+  template<size_t PaddingValue, class PaddingValueType>
+  void test_transposed_layout_left_padded(PaddingValueType runtime_padding_value)
   {
     auto test_one = [=] (auto in_exts, auto out_exts,
                          std::vector<char>& fake_storage)
@@ -248,8 +248,8 @@ namespace {
     }
   }
 
-  template<size_t PaddingValue>
-  void test_transposed_layout_right_padded(auto runtime_padding_value)
+  template<size_t PaddingValue, class PaddingValueType>
+  void test_transposed_layout_right_padded(PaddingValueType runtime_padding_value)
   {
     auto test_one = [=] (auto in_exts, auto out_exts,
                          std::vector<char>& fake_storage)