From 8579b2b494cff3ec2c5b33ba3cbbc3500fab3fc4 Mon Sep 17 00:00:00 2001
From: Cedric Nugteren <web@cedricnugteren.nl>
Date: Fri, 27 Oct 2017 21:53:19 +0200
Subject: Added a DTRSM C++ interface example

---
 samples/dtrsm.cpp | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 samples/dtrsm.cpp

(limited to 'samples/dtrsm.cpp')

diff --git a/samples/dtrsm.cpp b/samples/dtrsm.cpp
new file mode 100644
index 00000000..6d37dad7
--- /dev/null
+++ b/samples/dtrsm.cpp
@@ -0,0 +1,117 @@
+
+// =================================================================================================
+// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
+// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
+// width of 100 characters per line.
+//
+// Author(s):
+//   Cedric Nugteren <www.cedricnugteren.nl>
+//
+// This file demonstrates the use of the DTRSM routine. It is a stand-alone example, but it does
+// require the Khronos C++ OpenCL API header file (downloaded by CMake). The example uses C++
+// features, but CLBlast can also be used using the regular C-style OpenCL API.
+//
+// Note that this example is meant for illustration purposes only. CLBlast provides other programs
+// for performance benchmarking ('client_xxxxx') and for correctness testing ('test_xxxxx').
+//
+// =================================================================================================
+
+#include <cstdio>
+#include <vector>
+
+#define CL_USE_DEPRECATED_OPENCL_1_1_APIS // to disable deprecation warnings
+#define CL_USE_DEPRECATED_OPENCL_1_2_APIS // to disable deprecation warnings
+
+// Includes the C++ OpenCL API. If not yet available, it can be found here:
+// https://www.khronos.org/registry/cl/api/1.1/cl.hpp
+#include "cl.hpp"
+
+// Includes the CLBlast library
+#include <clblast.h>
+
+// =================================================================================================
+
+// Example use of the double-precision Xtrsm routine DTRSM, solving A*X = alpha*B, storing the
+// result in the memory of matrix B. Uses row-major storage (C-style).
+int main() {
+
+  // OpenCL platform/device settings
+  const auto platform_id = 0;
+  const auto device_id = 0;
+
+  // Example TRSM arguments
+  const size_t m = 4;
+  const size_t n = 3;
+  const double alpha = 1.0;
+  const auto a_ld = m;
+  const auto b_ld = n;
+
+  // Initializes the OpenCL platform
+  auto platforms = std::vector<cl::Platform>();
+  cl::Platform::get(&platforms);
+  if (platforms.size() == 0 || platform_id >= platforms.size()) { return 1; }
+  auto platform = platforms[platform_id];
+
+  // Initializes the OpenCL device
+  auto devices = std::vector<cl::Device>();
+  platform.getDevices(CL_DEVICE_TYPE_ALL, &devices);
+  if (devices.size() == 0 || device_id >= devices.size()) { return 1; }
+  auto device = devices[device_id];
+
+  // Creates the OpenCL context, queue, and an event
+  auto device_as_vector = std::vector<cl::Device>{device};
+  auto context = cl::Context(device_as_vector);
+  auto queue = cl::CommandQueue(context, device);
+  auto event = cl_event{nullptr};
+
+  // Populate host matrices with some example data
+  auto host_a = std::vector<double>({1.0,  2.0,  1.0, -2.0,
+                                    0.0, -1.0, -2.0,  0.0,
+                                    0.0,  0.0,  1.0,  1.0,
+                                    0.0,  0.0,  0.0, -1.0});
+  auto host_b = std::vector<double>({-1.0, -1.0,  3.0,
+                                     1.0, -3.0,  2.0,
+                                     1.0,  1.0, -1.0,
+                                     4.0, -1.0, -2.0});
+  // Expected result:
+  //   8 -5  2
+  // -11  3  4
+  //   5  0 -3
+  //  -4  1  2
+
+  // Copy the matrices to the device
+  auto device_a = cl::Buffer(context, CL_MEM_READ_WRITE, host_a.size()*sizeof(double));
+  auto device_b = cl::Buffer(context, CL_MEM_READ_WRITE, host_b.size()*sizeof(double));
+  queue.enqueueWriteBuffer(device_a, CL_TRUE, 0, host_a.size()*sizeof(double), host_a.data());
+  queue.enqueueWriteBuffer(device_b, CL_TRUE, 0, host_b.size()*sizeof(double), host_b.data());
+
+  // Call the DTRSM routine. Note that the type of alpha and beta (double) determine the precision.
+  auto queue_plain = queue();
+  auto status = clblast::Trsm(clblast::Layout::kRowMajor, clblast::Side::kLeft,
+                              clblast::Triangle::kUpper, clblast::Transpose::kNo,
+                              clblast::Diagonal::kNonUnit,
+                              m, n,
+                              alpha,
+                              device_a(), 0, a_ld,
+                              device_b(), 0, b_ld,
+                              &queue_plain, &event);
+
+  // Retrieves the results
+  if (status == clblast::StatusCode::kSuccess) {
+    clWaitForEvents(1, &event);
+    clReleaseEvent(event);
+  }
+  queue.enqueueReadBuffer(device_b, CL_TRUE, 0, host_b.size()*sizeof(double), host_b.data());
+
+  // Example completed. See "clblast.h" for status codes (0 -> success).
+  printf("Completed TRSM with status %d and results:\n", static_cast<int>(status));
+  for (auto i = size_t{0}; i < m; ++i) {
+    for (auto j = size_t{0}; j < n; ++j) {
+      printf("%3.0f ", host_b[i * b_ld + j]);
+    }
+    printf("\n");
+  }
+  return 0;
+}
+
+// =================================================================================================
-- 
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