skip BLAS and dense_matrix on Windows (matches C engine)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Transurgeon

.github/workflows/build-and-publish.yml

@@ -57,13 +57,6 @@ jobs:
         with:
           platforms: all
 
-      - name: Cache vcpkg packages
-        if: runner.os == 'Windows'
-        uses: actions/cache@v4
-        with:
-          path: C:\vcpkg\installed
-          key: vcpkg-windows-openblas-v1
-
       - name: Build wheels
         uses: pypa/cibuildwheel@v3.3.0
         env:
@@ -72,9 +65,6 @@ jobs:
           CIBW_ARCHS_MACOS: "x86_64 universal2"
           CIBW_ARCHS_LINUX: "auto aarch64"
           CIBW_BEFORE_BUILD_LINUX: "yum install -y openblas-devel || apt-get install -y libopenblas-dev"
-          CIBW_BEFORE_BUILD_WINDOWS: "vcpkg install openblas:x64-windows && dir C:\\vcpkg\\installed\\x64-windows\\include\\ && dir C:\\vcpkg\\installed\\x64-windows\\lib\\"
-          CIBW_ENVIRONMENT_WINDOWS: "VCPKG_INSTALLED_DIR=C:/vcpkg/installed/x64-windows"
-
       - name: Check wheels
         shell: bash
         run: |

setup.py

@@ -36,9 +36,13 @@ def finalize_options(self) -> None:
 
 
 # Collect all C source files from SparseDiffEngine
+_exclude = {"dnlp_diff_engine"}
+if system == "windows":
+    _exclude.add("dense_matrix")
+
 diff_engine_sources = [
     s for s in glob.glob("SparseDiffEngine/src/**/*.c", recursive=True)
-    if "dnlp_diff_engine" not in s
+    if not any(ex in s for ex in _exclude)
 ] + ["sparsediffpy/_bindings/bindings.c"]
 
 # Define _POSIX_C_SOURCE on Linux for clock_gettime and struct timespec
@@ -54,16 +58,9 @@ def finalize_options(self) -> None:
     blas_link_args = ["-lopenblas"]
     blas_include_dirs = ["/usr/include/openblas"]
 else:
-    # Windows: OpenBLAS via vcpkg
-    vcpkg_root = os.environ.get(
-        "VCPKG_INSTALLED_DIR",
-        r"C:\vcpkg\installed\x64-windows",
-    )
-    blas_link_args = [os.path.join(vcpkg_root, "lib", "openblas.lib")]
-    blas_include_dirs = [
-        os.path.join(vcpkg_root, "include"),
-        os.path.join(vcpkg_root, "include", "openblas"),
-    ]
+    # Windows: no BLAS available
+    blas_link_args = []
+    blas_include_dirs = []
 
 sparsediffengine = Extension(
     "sparsediffpy._sparsediffengine",