Mr/python bindings

.dockerignore

@@ -0,0 +1,5 @@
+build/
+.venv/
+__pycache__/
+*.pyc
+.git/

.github/workflows/cmake-build.yml

@@ -0,0 +1,83 @@
+name: CMake Build
+
+on:
+  pull_request:
+    branches: [master]
+
+jobs:
+  build-python:
+    name: Python bindings
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install -y libeigen3-dev nlohmann-json3-dev
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Configure
+        run: cmake --preset python -DRCQP_GENERATE_PYI=OFF
+
+      - name: Build
+        run: cmake --build --preset python -- -j$(nproc)
+
+  build-julia:
+    name: Julia bindings
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install -y libeigen3-dev nlohmann-json3-dev
+
+      - name: Set up Julia
+        uses: julia-actions/setup-julia@v2
+        with:
+          version: "1"
+
+      - name: Install CxxWrap.jl
+        run: julia --startup-file=no -e 'using Pkg; Pkg.add("CxxWrap")'
+
+      - name: Configure
+        run: cmake --preset julia
+
+      - name: Build
+        run: cmake --build --preset julia -- -j$(nproc)
+
+  build-all:
+    name: Python + Julia bindings
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install -y libeigen3-dev nlohmann-json3-dev
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Set up Julia
+        uses: julia-actions/setup-julia@v2
+        with:
+          version: "1"
+
+      - name: Install CxxWrap.jl
+        run: julia --startup-file=no -e 'using Pkg; Pkg.add("CxxWrap")'
+
+      - name: Configure
+        run: cmake --preset all -DRCQP_GENERATE_PYI=OFF
+
+      - name: Build
+        run: cmake --build --preset all -- -j$(nproc)

.gitignore

@@ -1,2 +1,3 @@
 .vscode
-build/*
+build/*
+.venv/

.python-version

@@ -0,0 +1 @@
+3.9

CMakeLists.txt

@@ -1,67 +1,166 @@
-cmake_minimum_required(VERSION 3.10.2)
-project(rcqp)
+cmake_minimum_required(VERSION 3.28)  # 3.28 needed for EXCLUDE_FROM_ALL in FetchContent_Declare
+
+project(rcqp LANGUAGES C CXX)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+# ---------------------------------------------------------------------------
+# Build options
+# ---------------------------------------------------------------------------
+option(RCQP_BUILD_PYTHON  "Build Python bindings"                   ON)
+option(RCQP_BUILD_JULIA   "Build Julia bindings"                    ON)
+option(RCQP_GENERATE_PYI  "Generate .pyi stubs via pybind11-stubgen" ON)
+
+# ---------------------------------------------------------------------------
+# Output directories  (keeps build/ tidy)
+# ---------------------------------------------------------------------------
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+
+# ---------------------------------------------------------------------------
 # Dependencies
-find_package(Eigen3 3.3 REQUIRED NO_MODULE)   # provides Eigen3::Eigen
-find_package(QDLDL)
+# ---------------------------------------------------------------------------
+include(FetchContent)
+
+find_package(Eigen3 3.3 REQUIRED NO_MODULE)
 find_package(nlohmann_json CONFIG REQUIRED)
 
-if(NOT QDLDL_FOUND)
-    include(FetchContent)
+# QDLDL – prefer a system install, otherwise fetch as static-only.
+# EXCLUDE_FROM_ALL suppresses QDLDL's cmake --install rules so they don't
+# interfere with pip install / scikit-build-core (requires CMake 3.28).
+find_package(qdldl CONFIG QUIET)
+if(NOT qdldl_FOUND)
+    set(QDLDL_BUILD_STATIC_LIB ON  CACHE BOOL "" FORCE)
+    set(QDLDL_BUILD_SHARED_LIB OFF CACHE BOOL "" FORCE)
+    set(QDLDL_BUILD_DEMO_EXE   OFF CACHE BOOL "" FORCE)
+    set(QDLDL_UNITTESTS        OFF CACHE BOOL "" FORCE)
     FetchContent_Declare(
-      qdldl
-      GIT_REPOSITORY https://github.com/oxfordcontrol/QDLDL.git
-      GIT_TAG master
+        qdldl
+        GIT_REPOSITORY https://github.com/osqp/qdldl.git
+        GIT_TAG        master
+        EXCLUDE_FROM_ALL
     )
     FetchContent_MakeAvailable(qdldl)
-    # If the fetched project provides a target, use it; otherwise adjust below.
 endif()
 
-# Create alias if needed for consistent naming
-if(NOT TARGET qdldl::qdldl)
-    if(TARGET qdldl)
-        add_library(qdldl::qdldl ALIAS qdldl)
-    endif()
+# Normalise QDLDL to a single interface target regardless of how it was found
+add_library(rcqp_qdldl INTERFACE)
+if(TARGET qdldl::qdldlstatic)
+    target_link_libraries(rcqp_qdldl INTERFACE qdldl::qdldlstatic)
+elseif(TARGET qdldl::qdldl)
+    target_link_libraries(rcqp_qdldl INTERFACE qdldl::qdldl)
+elseif(TARGET qdldlstatic)
+    target_link_libraries(rcqp_qdldl INTERFACE qdldlstatic)
+elseif(TARGET qdldl)
+    target_link_libraries(rcqp_qdldl INTERFACE qdldl)
+else()
+    message(FATAL_ERROR "Could not find a usable QDLDL target")
 endif()
 
-find_package(JlCxx)
-get_target_property(JlCxx_location JlCxx::cxxwrap_julia LOCATION)
-get_filename_component(JlCxx_location ${JlCxx_location} DIRECTORY)
-set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib;${JlCxx_location}")
+# ---------------------------------------------------------------------------
+# Core library  (static → gets bundled into each wrapper, no rpath issues)
+# ---------------------------------------------------------------------------
+add_library(rcqp STATIC
+    src/solver.cpp
+    src/problem.cpp
+    src/workspace.cpp
+    src/filter.cpp
+)
+target_include_directories(rcqp PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_link_libraries(rcqp PUBLIC Eigen3::Eigen nlohmann_json::nlohmann_json rcqp_qdldl)
 
-message(STATUS "Found JlCxx at ${JlCxx_location}")
+# ---------------------------------------------------------------------------
+# Python bindings  (cmake -DRCQP_BUILD_PYTHON=ON  — default ON)
+# ---------------------------------------------------------------------------
+if(RCQP_BUILD_PYTHON)
+    find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 
-# Setup library
-add_library(rcqp SHARED
-  ${CMAKE_CURRENT_SOURCE_DIR}/src/solver.cpp
-  ${CMAKE_CURRENT_SOURCE_DIR}/src/problem.cpp
-  ${CMAKE_CURRENT_SOURCE_DIR}/src/workspace.cpp
-  ${CMAKE_CURRENT_SOURCE_DIR}/src/filter.cpp
-)
+    find_package(pybind11 CONFIG QUIET)
+    if(NOT pybind11_FOUND)
+        FetchContent_Declare(
+            pybind11
+            GIT_REPOSITORY https://github.com/pybind/pybind11.git
+            GIT_TAG        v2.13.6
+        )
+        FetchContent_MakeAvailable(pybind11)
+    endif()
 
-target_include_directories(rcqp
-  PUBLIC
-    ${CMAKE_CURRENT_SOURCE_DIR}/include
-)
+    pybind11_add_module(rcqp_python MODULE bindings/python_bindings.cpp)
+    target_link_libraries(rcqp_python PRIVATE rcqp)
+    set_target_properties(rcqp_python PROPERTIES
+        OUTPUT_NAME            rcqp
+        LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/python
+    )
+
+    # .pyi stub generation (for VSCode / Pylance autocomplete)
+    if(RCQP_GENERATE_PYI)
+        find_program(PYBIND11_STUBGEN pybind11-stubgen)
+        if(PYBIND11_STUBGEN)
+            add_custom_command(TARGET rcqp_python POST_BUILD
+                COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_SOURCE_DIR}/typings
+                COMMAND ${CMAKE_COMMAND} -E env
+                        PYTHONPATH=${CMAKE_BINARY_DIR}/python
+                        ${PYBIND11_STUBGEN} rcqp
+                        --output-dir ${CMAKE_SOURCE_DIR}/typings
+                        --numpy-array-remove-parameters
+                        --ignore-unresolved-names "^(m|n)$"
+                COMMENT "Generating rcqp.pyi stubs"
+                VERBATIM
+            )
+        else()
+            message(WARNING
+                "pybind11-stubgen not found — .pyi stubs won't be regenerated. "
+                "Run: pip install pybind11-stubgen")
+        endif()
+    endif()
+
+    install(TARGETS rcqp_python LIBRARY DESTINATION .)
+endif()
 
-target_compile_features(rcqp PUBLIC cxx_std_17)
-
-# Wrapper library for Julia
-add_library(rcqp_wrapper SHARED wrapper.cpp)
-target_link_libraries(rcqp_wrapper 
-    PRIVATE 
-    rcqp
-    JlCxx::cxxwrap_julia)
-
-# Link dependencies 
-target_link_libraries(rcqp
-  PUBLIC
-    Eigen3::Eigen
-    qdldl
-    nlohmann_json::nlohmann_json
-)
+# ---------------------------------------------------------------------------
+# Julia bindings  (cmake -DRCQP_BUILD_JULIA=ON)
+# ---------------------------------------------------------------------------
+if(RCQP_BUILD_JULIA)
+    # Auto-detect JlCxx prefix by asking Julia where CxxWrap installed it.
+    # This works on any machine that has Julia + CxxWrap.jl without any
+    # hardcoded paths. Users can still override with -DJlCxx_DIR=<path>.
+    if(NOT DEFINED JlCxx_DIR)
+        find_program(JULIA_EXECUTABLE julia)
+        if(JULIA_EXECUTABLE)
+            execute_process(
+                COMMAND ${JULIA_EXECUTABLE} --startup-file=no -e
+                        "using CxxWrap; print(CxxWrap.prefix_path())"
+                OUTPUT_VARIABLE _jlcxx_prefix
+                ERROR_QUIET
+                OUTPUT_STRIP_TRAILING_WHITESPACE
+            )
+            if(_jlcxx_prefix)
+                set(JlCxx_DIR "${_jlcxx_prefix}/lib/cmake/JlCxx"
+                    CACHE PATH "Path to JlCxxConfig.cmake (auto-detected from Julia)")
+                message(STATUS "Auto-detected JlCxx_DIR: ${JlCxx_DIR}")
+            else()
+                message(FATAL_ERROR
+                    "Could not detect JlCxx prefix from Julia.\n"
+                    "Make sure CxxWrap.jl is installed: julia -e 'using Pkg; Pkg.add(\"CxxWrap\")'\n"
+                    "Or set JlCxx_DIR manually: cmake -DJlCxx_DIR=<path/to/cmake/JlCxx>")
+            endif()
+        else()
+            message(FATAL_ERROR
+                "julia executable not found.\n"
+                "Install Julia from https://julialang.org/downloads or set JlCxx_DIR manually.")
+        endif()
+    endif()
+
+    find_package(JlCxx REQUIRED)
+    add_library(rcqp_julia SHARED bindings/julia_bindings.cpp)
+    target_link_libraries(rcqp_julia PRIVATE rcqp JlCxx::cxxwrap_julia)
+    set_target_properties(rcqp_julia PROPERTIES
+        LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib
+    )
+endif()

CMakePresets.json

@@ -0,0 +1,42 @@
+{
+  "version": 3,
+  "configurePresets": [
+    {
+      "name": "python",
+      "displayName": "Python bindings only",
+      "binaryDir": "${sourceDir}/build",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE":   "Release",
+        "RCQP_BUILD_PYTHON":  "ON",
+        "RCQP_BUILD_JULIA":   "OFF",
+        "RCQP_GENERATE_PYI":  "ON"
+      }
+    },
+    {
+      "name": "julia",
+      "displayName": "Julia bindings only (requires Julia + CxxWrap.jl)",
+      "binaryDir": "${sourceDir}/build",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE":   "Release",
+        "RCQP_BUILD_PYTHON":  "OFF",
+        "RCQP_BUILD_JULIA":   "ON"
+      }
+    },
+    {
+      "name": "all",
+      "displayName": "Python + Julia bindings (requires Julia + CxxWrap.jl)",
+      "binaryDir": "${sourceDir}/build",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE":   "Release",
+        "RCQP_BUILD_PYTHON":  "ON",
+        "RCQP_BUILD_JULIA":   "ON",
+        "RCQP_GENERATE_PYI":  "ON"
+      }
+    }
+  ],
+  "buildPresets": [
+    { "name": "python", "configurePreset": "python" },
+    { "name": "julia",  "configurePreset": "julia"  },
+    { "name": "all",    "configurePreset": "all"    }
+  ]
+}