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// =================================================================================================
// 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 HAXPY routine. It demonstrates the use of half-precision.
//
// 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_USE_DEPRECATED_OPENCL_1_2_APIS // to disable deprecation warnings
// Includes the CLBlast library (C interface)
#include <clblast_c.h>
// Includes the float-to-half and half-to-float conversion utilities
#include <clblast_half.h>
// =================================================================================================
// Example use of the half-precision routine HAXPY
int main(void) {
// OpenCL platform/device settings
const size_t platform_id = 0;
const size_t device_id = 0;
// Example HAXPY arguments
const size_t n = 8192;
const cl_half alpha = FloatToHalf(0.5f);
// 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 vectors with some example data
cl_half* host_a = (cl_half*)malloc(sizeof(cl_half)*n);
cl_half* host_b = (cl_half*)malloc(sizeof(cl_half)*n);
for (size_t i=0; i<n; ++i) { host_a[i] = FloatToHalf(2.2f); }
for (size_t i=0; i<n; ++i) { host_b[i] = FloatToHalf(0.4f); }
printf("Input values at index 0: alpha * a[0] + b[0] == %.3lf * %.3lf + %.3lf\n",
HalfToFloat(alpha), HalfToFloat(host_a[0]), HalfToFloat(host_b[0]));
// Copy the matrices to the device
cl_mem device_a = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(cl_half), NULL, NULL);
cl_mem device_b = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(cl_half), NULL, NULL);
clEnqueueWriteBuffer(queue, device_a, CL_TRUE, 0, n*sizeof(cl_half), host_a, 0, NULL, NULL);
clEnqueueWriteBuffer(queue, device_b, CL_TRUE, 0, n*sizeof(cl_half), host_b, 0, NULL, NULL);
// Call the HAXPY routine.
CLBlastStatusCode status = CLBlastHaxpy(n, alpha,
device_a, 0, 1,
device_b, 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_b, CL_TRUE, 0, n*sizeof(cl_half), host_b, 0, NULL, NULL);
// Example completed. See "clblast_c.h" for status codes (0 -> success).
printf("Completed HAXPY with status %d\n", status);
// Prints the first output value
if (status == 0) {
printf("Output value at index 0: b[0] = %.3lf\n", HalfToFloat(host_b[0]));
}
// Clean-up
free(platforms);
free(devices);
free(host_a);
free(host_b);
clReleaseMemObject(device_a);
clReleaseMemObject(device_b);
clReleaseCommandQueue(queue);
clReleaseContext(context);
return 0;
}
// =================================================================================================
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