Adding HPX backend (train,predict and tests) based on hpx::for_each and hpx::experimental::for_loop

.clang-format

@@ -79,7 +79,7 @@ IncludeBlocks: Regroup
 IncludeCategories:
   - Regex: '^"plssvm/'
     Priority: 1
-  - Regex: '^"(cuda|hip|CL|sycl|omp)'
+  - Regex: '^"(cuda|hip|CL|sycl|omp|hpx)'
     Priority: 2
   - Regex: '^"(tests|bindings)/'
     Priority: 3

CMakeLists.txt

@@ -1,4 +1,4 @@
-## Authors: Alexander Van Craen, Marcel Breyer
+## Authors: Alexander Van Craen, Marcel Breyer, Alexander Strack
 ## Copyright (C): 2018-today The PLSSVM project - All Rights Reserved
 ## License: This file is part of the PLSSVM project which is released under the MIT license.
 ##          See the LICENSE.md file in the project root for full license information.
@@ -376,6 +376,13 @@ if (PLSSVM_ENABLE_STDPAR_BACKEND MATCHES "AUTO" OR PLSSVM_ENABLE_STDPAR_BACKEND)
     add_subdirectory(src/plssvm/backends/stdpar)
 endif ()
 
+## check for HPX backend
+set(PLSSVM_ENABLE_HPX_BACKEND AUTO CACHE STRING "Enable HPX Backend")
+set_property(CACHE PLSSVM_ENABLE_HPX_BACKEND PROPERTY STRINGS AUTO ON OFF)
+if (PLSSVM_ENABLE_HPX_BACKEND MATCHES "AUTO" OR PLSSVM_ENABLE_HPX_BACKEND)
+    add_subdirectory(src/plssvm/backends/HPX)
+endif ()
+
 ## check for CUDA backend
 set(PLSSVM_ENABLE_CUDA_BACKEND AUTO CACHE STRING "Enable CUDA Backend")
 set_property(CACHE PLSSVM_ENABLE_CUDA_BACKEND PROPERTY STRINGS AUTO ON OFF)
@@ -705,6 +712,10 @@ if (TARGET ${PLSSVM_STDPAR_BACKEND_LIBRARY_NAME})
     message(STATUS "${PLSSVM_STDPAR_BACKEND_SUMMARY_STRING}")
     list(APPEND PLSSVM_BACKEND_NAME_LIST "stdpar")
 endif ()
+if (TARGET ${PLSSVM_HPX_BACKEND_LIBRARY_NAME})
+    message(STATUS "${PLSSVM_HPX_BACKEND_SUMMARY_STRING}")
+    list(APPEND PLSSVM_BACKEND_NAME_LIST "hpx")
+endif ()
 if (TARGET ${PLSSVM_CUDA_BACKEND_LIBRARY_NAME})
     message(STATUS "${PLSSVM_CUDA_BACKEND_SUMMARY_STRING}")
     list(APPEND PLSSVM_BACKEND_NAME_LIST "cuda")
@@ -847,6 +858,7 @@ install(FILES
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmHIPTargets.cmake"
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmOpenCLTargets.cmake"
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmOpenMPTargets.cmake"
+        "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmHPXTargets.cmake"
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmAdaptiveCppTargets.cmake"
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmDPCPPTargets.cmake"
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/plssvm/plssvmstdparTargets.cmake"

CMakePresets.json

@@ -2,6 +2,7 @@
   "version": 6,
   "include": [
     "cmake/presets/openmp.json",
+    "cmake/presets/hpx.json",
     "cmake/presets/stdpar.json",
     "cmake/presets/stdpar_gcc.json",
     "cmake/presets/stdpar_nvhpc.json",
@@ -15,4 +16,4 @@
     "cmake/presets/dpcpp.json",
     "cmake/presets/all.json"
   ]
-}
+}

README.md

@@ -57,6 +57,7 @@ The main highlights of our SVM implementations are:
 1. Drop-in replacement for LIBSVM's `svm-train`, `svm-predict`, and `svm-scale` (some features currently not implemented).
 2. Support of multiple different programming frameworks for parallelization (also called backends in our PLSSVM implementation) which allows us to target GPUs and CPUs from different vendors like NVIDIA, AMD, or Intel:
    - [OpenMP](https://www.openmp.org/)
+   - [HPX](https://hpx.stellar-group.org/)
    - [stdpar](https://en.cppreference.com/w/cpp/algorithm) (supported implementations are [nvc++](https://developer.nvidia.com/hpc-sdk) from NVIDIA's HPC SDK, [roc-stdpar](https://github.com/ROCm/roc-stdpar) as a patched LLVM, [icpx](https://www.intel.com/content/www/us/en/developer/tools/oneapi/dpc-compiler.html) as Intel's oneAPI compiler, [AdaptiveCpp](https://github.com/AdaptiveCpp/AdaptiveCpp), and [GNU GCC](https://gcc.gnu.org/) using TBB). <br>
      **Note**: due to the nature of the used USM mechanics in the `stdpar` implementations, the `stdpar` backend **can't** be enabled together with **any** other backend! <br>
      **Note**: since every translation units need to be compiled with the same flag, we currently globally set `CMAKE_CXX_FLAGS` although it's discouraged in favor of `target_compile_options`.
@@ -105,6 +106,10 @@ Additional dependencies for the stdpar backend:
 
 - compiler with stdpar support
 
+Additional dependencies for the HPX backend:
+
+- [HPX ≥ v1.9.0](https://hpx.stellar-group.org/)
+
 Additional dependencies for the CUDA backend:
 
 - CUDA SDK
@@ -355,6 +360,9 @@ Available configure presets:
   "openmp"                  - OpenMP backend
   "openmp_python"           - OpenMP backend + Python bindings
   "openmp_test"             - OpenMP backend tests
+  "hpx"                     - HPX backend
+  "hpx_python"              - HPX backend + Python bindings
+  "hpx_test"                - HPX backend tests
   "cuda"                    - CUDA backend
   "cuda_python"             - CUDA backend + Python bindings
   "cuda_test"               - CUDA backend tests
@@ -545,7 +553,7 @@ Usage:
   -i, --max_iter arg            set the maximum number of CG iterations (default: num_features)
   -l, --solver arg              choose the solver: automatic|cg_explicit|cg_implicit (default: automatic)
   -a, --classification arg      the classification strategy to use for multi-class classification: oaa|oao (default: oaa)
-  -b, --backend arg             choose the backend: automatic|openmp|cuda|hip|opencl|sycl|stdpar (default: automatic)
+  -b, --backend arg             choose the backend: automatic|openmp|hpx|cuda|hip|opencl|sycl|stdpar (default: automatic)
   -p, --target_platform arg     choose the target platform: automatic|cpu|gpu_nvidia|gpu_amd|gpu_intel (default: automatic)
       --sycl_kernel_invocation_type arg
                                 choose the kernel invocation type when using SYCL as backend: automatic|nd_range (default: automatic)
@@ -589,13 +597,14 @@ The `--backend=automatic` option works as follows:
 - if the `gpu_nvidia` target is available, check for existing backends in order `cuda` 🠦 `hip` 🠦 `opencl` 🠦 `sycl` 🠦 `stdpar`
 - otherwise, if the `gpu_amd` target is available, check for existing backends in order `hip` 🠦 `opencl` 🠦 `sycl` 🠦 `stdpar`
 - otherwise, if the `gpu_intel` target is available, check for existing backends in order `sycl` 🠦 `opencl` 🠦 `stdpar`
-- otherwise, if the `cpu` target is available, check for existing backends in order `sycl` 🠦 `opencl` 🠦 `openmp` 🠦 `stdpar`
+- otherwise, if the `cpu` target is available, check for existing backends in order `sycl` 🠦 `opencl` 🠦 `openmp` 🠦 `hpx` 🠦 `stdpar`
 
 Note that during CMake configuration it is guaranteed that at least one of the above combinations does exist.
 
 The `--target_platform=automatic` option works for the different backends as follows:
 
 - `OpenMP`: always selects a CPU
+- `HPX`: always selects a CPU
 - `CUDA`: always selects an NVIDIA GPU (if no NVIDIA GPU is available, throws an exception)
 - `HIP`: always selects an AMD GPU (if no AMD GPU is available, throws an exception)
 - `OpenCL`: tries to find available devices in the following order: NVIDIA GPUs 🠦 AMD GPUs 🠦 Intel GPUs 🠦 CPU

bindings/Python/CMakeLists.txt

@@ -1,4 +1,4 @@
-## Authors: Alexander Van Craen, Marcel Breyer
+## Authors: Alexander Van Craen, Marcel Breyer, Alexander Strack
 ## Copyright (C): 2018-today The PLSSVM project - All Rights Reserved
 ## License: This file is part of the PLSSVM project which is released under the MIT license.
 ##          See the LICENSE.md file in the project root for full license information.
@@ -68,6 +68,9 @@ endif ()
 if (TARGET ${PLSSVM_OPENMP_BACKEND_LIBRARY_NAME})
     list(APPEND PLSSVM_PYTHON_BINDINGS_SOURCES ${CMAKE_CURRENT_LIST_DIR}/backends/openmp_csvm.cpp)
 endif ()
+if (TARGET ${PLSSVM_HPX_BACKEND_LIBRARY_NAME})
+    list(APPEND PLSSVM_PYTHON_BINDINGS_SOURCES ${CMAKE_CURRENT_LIST_DIR}/backends/hpx_csvm.cpp)
+endif ()
 if (TARGET ${PLSSVM_STDPAR_BACKEND_LIBRARY_NAME})
 
     # AdaptiveCpp stdpar only support on the CPU when using our Python bindings
@@ -125,4 +128,4 @@ target_compile_options(${PLSSVM_BASE_LIBRARY_NAME} PUBLIC $<$<COMPILE_LANG_AND_I
 target_compile_options(${PLSSVM_BASE_LIBRARY_NAME} PUBLIC -fPIC)
 
 # append pybind11 bindings library to installed targets
-append_local_and_parent(PLSSVM_TARGETS_TO_INSTALL ${PLSSVM_PYTHON_BINDINGS_LIBRARY_NAME})
+append_local_and_parent(PLSSVM_TARGETS_TO_INSTALL ${PLSSVM_PYTHON_BINDINGS_LIBRARY_NAME})

bindings/Python/README.md

@@ -10,7 +10,7 @@
         - [plssvm.Parameter](#plssvmparameter)
         - [plssvm.DataSet](#plssvmdataset)
         - [plssvm.CSVM](#plssvmcsvm)
-        - [plssvm.openmp.CSVM, plssvm.stdpar.CSVM, plssvm.cuda.CSVM, plssvm.hip.CSVM, plssvm.opencl.CSVM, plssvm.sycl.CSVM, plssvm.dpcpp.CSVM, plssvm.adaptivecpp.CSVM](#plssvmopenmpcsvm-plssvmcudacsvm-plssvmhipcsvm-plssvmopenclcsvm-plssvmsyclcsvm-plssvmdpcppcsvm-plssvmadaptivecppcsvm)
+        - [plssvm.openmp.CSVM, plssvm.hpx.CSVM, plssvm.stdpar.CSVM, plssvm.cuda.CSVM, plssvm.hip.CSVM, plssvm.opencl.CSVM, plssvm.sycl.CSVM, plssvm.dpcpp.CSVM, plssvm.adaptivecpp.CSVM](#plssvmopenmpcsvm-plssvmhpxcsvm-plssvmcudacsvm-plssvmhipcsvm-plssvmopenclcsvm-plssvmsyclcsvm-plssvmdpcppcsvm-plssvmadaptivecppcsvm)
         - [plssvm.Model](#plssvmmodel)
         - [plssvm.Version](#plssvmversion)
         - [plssvm.environment.ScopeGuard](#plssvmenvironmentscopeguard)
@@ -196,7 +196,7 @@ The following table lists all PLSSVM enumerations exposed on the Python side:
 | `FileFormatType`       | `LIBSVM`, `ARFF`                                                     | The different supported file format types (default: `LIBSVM`).                                                                                                                                                                                              |
 | `GammaCoefficientType` | `AUTOMATIC`, `SCALE`                                                 | The different modes for the dynamic gamma calculation (default: `AUTOMATIC`).                                                                                                                                                                               |
 | `ClassificationType`   | `OAA`, `OAO`                                                         | The different supported multi-class classification strategies (default: `LIBSVM`).                                                                                                                                                                          |
-| `BackendType`          | `AUTOMATIC`, `OPENMP`, `CUDA`, `HIP`, `OPENCL`, `SYCL`               | The different supported backends (default: `AUTOMATIC`). If `AUTOMATIC` is provided, the selected backend depends on the used target platform.                                                                                                              |
+| `BackendType`          | `AUTOMATIC`, `OPENMP`, `HPX`, `CUDA`, `HIP`, `OPENCL`, `SYCL`        | The different supported backends (default: `AUTOMATIC`). If `AUTOMATIC` is provided, the selected backend depends on the used target platform.                                                                                                              |
 | `VerbosityLevel`       | `QUIET`, `LIBSVM`, `TIMING`, `FULL`                                  | The different supported log levels (default: `FULL`). `QUIET` means no output, `LIBSVM` output that is as conformant as possible with LIBSVM's output, `TIMING` all timing related outputs, and `FULL` everything. Can be combined via bit-wise operations. |
 | `Status`               | `UNINITIALIZED`, `INITIALIZED`, `FINALIZED`, `UNNECESSARY`           | The different environment status values. **Note**: located in the `plssvm.environment` module.                                                                                                                                                              |                                                                                                                                                                                                                   |
 
@@ -337,6 +337,10 @@ If the most performant backend should be used, it is sufficient to use `plssvm.C
 `sycl_implementation_type` to choose between DPC++ and AdaptiveCpp as SYCL implementations
 and `sycl_kernel_invocation_type` to choose between the two different SYCL kernel invocation types.
 
+**Note**: if the backend type is `plssvm.BackendType.HPX` it is necessary to initialize and finalize the HPX runtime.
+The runtime can be manually managed using `plssvm.environment.initialize()` and `plssvm.environment.finalize()`.
+We recommend utilizing `plssvm.environment.ScopeGuard()` to manage the lifetime of the HPX runtime automatically.
+
 | methods                                                                                                                                      | description                                                                                                                                                                                                         |
 |----------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | `set_params(params)`                                                                                                                         | Replace the current `plssvm.Parameter` with the provided one.                                                                                                                                                       |
@@ -349,7 +353,7 @@ and `sycl_kernel_invocation_type` to choose between the two different SYCL kerne
 | `score(model)`                                                                                                                               | Score the model with respect to itself returning its accuracy.                                                                                                                                                      |
 | `score(model, data_set)`                                                                                                                     | Score the model given the provided data set returning its accuracy.                                                                                                                                                 |
 
-#### `plssvm.openmp.CSVM`, `plssvm.stdpar.CSVM`, plssvm.cuda.CSVM`, `plssvm.hip.CSVM`, `plssvm.opencl.CSVM`, `plssvm.sycl.CSVM`, `plssvm.dpcpp.CSVM`, `plssvm.adaptivecpp.CSVM`
+#### `plssvm.openmp.CSVM`, `plssvm.hpx.CSVM`, `plssvm.stdpar.CSVM`, plssvm.cuda.CSVM`, `plssvm.hip.CSVM`, `plssvm.opencl.CSVM`, `plssvm.sycl.CSVM`, `plssvm.dpcpp.CSVM`, `plssvm.adaptivecpp.CSVM`
 
 These classes represent the backend specific CSVMs.
 **Note**: they are only available if the respective backend has been enabled during PLSSVM's build step.
@@ -560,4 +564,4 @@ The PLSSVM Python3 bindings define a few new exception types:
 | `ClassificationReportError`  | If something in the classification report went wrong. **Note**: shouldn't occur in user code.                          |
 | `EnvironmentError`           | If something during environment initialization or finalization went wrong.                                             |
 
-Depending on the available backends, additional `BackendError`s are also available (e.g., `plssvm.cuda.BackendError`).
+Depending on the available backends, additional `BackendError`s are also available (e.g., `plssvm.cuda.BackendError`).

bindings/Python/backend_types.cpp

@@ -1,6 +1,7 @@
 /**
  * @author Alexander Van Craen
  * @author Marcel Breyer
+ * @author Alexander Strack
  * @copyright 2018-today The PLSSVM project - All Rights Reserved
  * @license This file is part of the PLSSVM project which is released under the MIT license.
  *          See the LICENSE.md file in the project root for full license information.
@@ -20,6 +21,7 @@ void init_backend_types(py::module_ &m) {
     py::enum_<plssvm::backend_type>(m, "BackendType")
         .value("AUTOMATIC", plssvm::backend_type::automatic, "the default backend; depends on the specified target platform")
         .value("OPENMP", plssvm::backend_type::openmp, "OpenMP to target CPUs only (currently no OpenMP target offloading support)")
+        .value("HPX", plssvm::backend_type::hpx, "HPX to target CPUs only (currently no GPU executor support)")
         .value("STDPAR", plssvm::backend_type::stdpar, "C++ standard parallelism to target CPUs and GPUs from different vendors based on the used stdpar implementation; supported implementations are: nvhpc (nvc++), roc-stdpar, AdaptiveCpp, Intel LLVM (icpx), and GNU GCC + TBB")
         .value("CUDA", plssvm::backend_type::cuda, "CUDA to target NVIDIA GPUs only")
         .value("HIP", plssvm::backend_type::hip, "HIP to target AMD and NVIDIA GPUs")