From 7fab29304c682ea7f341b3338ddfbdd2d5b08cbf Mon Sep 17 00:00:00 2001
From: Cedric Nugteren <web@cedricnugteren.nl>
Date: Sun, 8 Mar 2020 11:26:18 +0100
Subject: Added sample to play around with XAMAX routine

---
 samples/samax.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 samples/samax.c

(limited to 'samples/samax.c')

diff --git a/samples/samax.c b/samples/samax.c
new file mode 100644
index 00000000..36e78846
--- /dev/null
+++ b/samples/samax.c
@@ -0,0 +1,102 @@
+
+// =================================================================================================
+// 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 iSAMAX routine. It is pure C99 and demonstrates the use of
+// the C API to the CLBlast library.
+//
+// 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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#define CL_TARGET_OPENCL_VERSION 110
+#define CL_USE_DEPRECATED_OPENCL_1_2_APIS // to disable deprecation warnings
+
+// Includes the CLBlast library (C interface)
+#include <clblast_c.h>
+
+// =================================================================================================
+
+// Example use of the single-precision routine iSAMAX
+int main(void) {
+
+  // OpenCL platform/device settings
+  const size_t platform_id = 0;
+  const size_t device_id = 0;
+
+  // Example iSAMAX arguments
+  const size_t n = 1000;
+
+  // Initializes the OpenCL platform
+  cl_uint num_platforms;
+  clGetPlatformIDs(0, NULL, &num_platforms);
+  cl_platform_id* platforms = (cl_platform_id*)malloc(num_platforms*sizeof(cl_platform_id));
+  clGetPlatformIDs(num_platforms, platforms, NULL);
+  cl_platform_id platform = platforms[platform_id];
+
+  // Initializes the OpenCL device
+  cl_uint num_devices;
+  clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 0, NULL, &num_devices);
+  cl_device_id* devices = (cl_device_id*)malloc(num_devices*sizeof(cl_device_id));
+  clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, num_devices, devices, NULL);
+  cl_device_id device = devices[device_id];
+
+  // Creates the OpenCL context, queue, and an event
+  cl_context context = clCreateContext(NULL, 1, &device, NULL, NULL, NULL);
+  cl_command_queue queue = clCreateCommandQueue(context, device, 0, NULL);
+  cl_event event = NULL;
+
+  // Populate host data structures with some example data
+  float* host_input = (float*)malloc(sizeof(float)*n);
+  unsigned int* host_output = (unsigned int*)malloc(sizeof(unsigned int)*1);
+  for (size_t i=0; i<n; ++i) { host_input[i] = (float)(i % 10); } // staircase modulo 10
+  for (size_t i=0; i<1; ++i) { host_output[i] = 77; }  // some temp value to be overwritten later
+
+  // Copy the data-structures to the device
+  cl_mem device_input = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(float), NULL, NULL);
+  cl_mem device_output = clCreateBuffer(context, CL_MEM_READ_WRITE, 1*sizeof(unsigned int), NULL, NULL);
+  clEnqueueWriteBuffer(queue, device_input, CL_TRUE, 0, n*sizeof(float), host_input, 0, NULL, NULL);
+  clEnqueueWriteBuffer(queue, device_output, CL_TRUE, 0, 1*sizeof(unsigned int), host_output, 0, NULL, NULL);
+
+  // Call the iSAMAX routine.
+  CLBlastStatusCode status = CLBlastiSamax(n,
+                                           device_output, 0,
+                                           device_input, 0, 1,
+                                           &queue, &event);
+
+  // Wait for completion
+  if (status == CLBlastSuccess) {
+    clWaitForEvents(1, &event);
+    clReleaseEvent(event);
+  }
+
+  // Copies the result back to the host
+  clEnqueueReadBuffer(queue, device_output, CL_TRUE, 0, 1*sizeof(unsigned int), host_output, 0, NULL, NULL);
+
+  // Example completed. See "clblast_c.h" for status codes (0 -> success).
+  printf("Completed iSAMAX with status %d: array of %d values with staircases from 0..9 repeated, max at index %zu with value %.0lf\n",
+         status, n, host_output[0], host_input[host_output[0]]);
+
+  // Clean-up
+  free(platforms);
+  free(devices);
+  free(host_input);
+  free(host_output);
+  clReleaseMemObject(device_input);
+  clReleaseMemObject(device_output);
+  clReleaseCommandQueue(queue);
+  clReleaseContext(context);
+  return 0;
+}
+
+// =================================================================================================
-- 
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