Add an example demonstrating use of Complex

Author: sbastrakov

example/CMakeLists.txt

@@ -29,6 +29,7 @@ project("alpakaExamples" LANGUAGES CXX)
 ################################################################################
 
 add_subdirectory("bufferCopy/")
+add_subdirectory("complex/")
 add_subdirectory("heatEquation/")
 add_subdirectory("helloWorld/")
 add_subdirectory("helloWorldLambda/")

example/complex/CMakeLists.txt

@@ -0,0 +1,60 @@
+#
+# Copyright 2014-2021 Erik Zenker, Benjamin Worpitz, Jan Stephan, Sergei Bastrakov
+#
+# This file exemplifies usage of alpaka.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED “AS IS” AND ISC DISCLAIMS ALL WARRANTIES WITH
+# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+# IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+
+################################################################################
+# Required CMake version.
+
+cmake_minimum_required(VERSION 3.15)
+
+set_property(GLOBAL PROPERTY USE_FOLDERS ON)
+
+################################################################################
+# Project.
+
+set(_TARGET_NAME complex)
+
+project(${_TARGET_NAME})
+
+#-------------------------------------------------------------------------------
+# Find alpaka.
+
+if(NOT TARGET alpaka::alpaka)
+    option(USE_ALPAKA_SOURCE_TREE "Use alpaka's source tree instead of an alpaka installation" OFF)
+
+    if(USE_ALPAKA_SOURCE_TREE)
+        # Don't build the examples recursively
+        set(alpaka_BUILD_EXAMPLES OFF)
+        add_subdirectory("${CMAKE_CURRENT_LIST_DIR}/../.." "${CMAKE_BINARY_DIR}/alpaka")
+    else()
+        find_package(alpaka REQUIRED)
+    endif()
+endif()
+
+#-------------------------------------------------------------------------------
+# Add executable.
+
+alpaka_add_executable(
+    ${_TARGET_NAME}
+    src/complex.cpp)
+target_link_libraries(
+    ${_TARGET_NAME}
+    PUBLIC alpaka::alpaka)
+
+set_target_properties(${_TARGET_NAME} PROPERTIES FOLDER example)
+
+add_test(NAME ${_TARGET_NAME} COMMAND ${_TARGET_NAME})

example/complex/src/complex.cpp

@@ -0,0 +1,110 @@
+/* Copyright 2021 Sergei Bastrakov
+ *
+ * This file exemplifies usage of alpaka.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS” AND ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <alpaka/alpaka.hpp>
+#include <alpaka/example/ExampleDefaultAcc.hpp>
+
+#include <cstdint>
+#include <iostream>
+
+
+//! Complex numbers demonstration kernel
+struct ComplexKernel
+{
+    template<typename TAcc>
+    ALPAKA_FN_ACC auto operator()(TAcc const& acc) const -> void
+    {
+        // alpaka::Complex<T> supports the same methods as std::complex<T>, they are also useable inside kernels
+        auto x = alpaka::Complex<float>(0.1f, 0.2f);
+        float const real = x.real();
+        auto y = alpaka::Complex<float>(0.3f, 0.4f);
+
+        // Operators are also the same
+        x *= 2.0f;
+        alpaka::Complex<float> z = x + y;
+
+        // In-kernel math functions are accessed via alpaka wrappers, the same way as for real numbers
+        float zAbs = alpaka::math::abs(acc, z);
+    }
+};
+
+auto main() -> int
+{
+// Fallback for the CI with disabled sequential backend
+#if defined(ALPAKA_CI) && !defined(ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED)
+    return EXIT_SUCCESS;
+#else
+    using Idx = std::size_t;
+
+    // Define the accelerator
+    //
+    // It is possible to choose from a set of accelerators:
+    // - AccGpuCudaRt
+    // - AccGpuHipRt
+    // - AccCpuThreads
+    // - AccCpuFibers
+    // - AccCpuOmp2Threads
+    // - AccCpuOmp2Blocks
+    // - AccOmp5
+    // - AccCpuTbbBlocks
+    // - AccCpuSerial
+    //
+    // Each accelerator has strengths and weaknesses. Therefore,
+    // they need to be choosen carefully depending on the actual
+    // use case. Furthermore, some accelerators only support a
+    // particular workdiv, but workdiv can also be generated
+    // automatically.
+
+    // By exchanging the Acc and Queue types you can select where to execute the kernel.
+    using Acc = alpaka::ExampleDefaultAcc<alpaka::DimInt<1>, Idx>;
+    std::cout << "Using alpaka accelerator: " << alpaka::getAccName<Acc>() << std::endl;
+
+    // Defines the synchronization behavior of a queue
+    using QueueProperty = alpaka::Blocking;
+    using Queue = alpaka::Queue<Acc, QueueProperty>;
+
+    // Select a device
+    auto const devAcc = alpaka::getDevByIdx<Acc>(0u);
+
+    // Create a queue on the device
+    Queue queue(devAcc);
+
+    // Define the work division
+    Idx const threadsPerGrid = 1u;
+    Idx const elementsPerThread = 1u;
+    auto const workDiv = alpaka::getValidWorkDiv<Acc>(
+        devAcc,
+        threadsPerGrid,
+        elementsPerThread,
+        false,
+        alpaka::GridBlockExtentSubDivRestrictions::Unrestricted);
+
+    // Run the kernel
+    alpaka::exec<Acc>(queue, workDiv, ComplexKernel{});
+    alpaka::wait(queue);
+
+    // Usage of alpaka::Complex<T> on the host side is the same as inside kernels, except math functions are not
+    // supported
+    auto x = alpaka::Complex<float>(0.1f, 0.2f);
+    float const real = x.real();
+    auto y = alpaka::Complex<float>(0.3f, 0.4f);
+    x *= 2.0f;
+    alpaka::Complex<float> z = x + y;
+
+    return EXIT_SUCCESS;
+#endif
+}