103 lines
4.2 KiB
C
103 lines
4.2 KiB
C
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// =================================================================================================
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// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
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// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
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// width of 100 characters per line.
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//
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// Author(s):
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// Cedric Nugteren <www.cedricnugteren.nl>
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//
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// This file demonstrates the use of the iSAMAX routine. It is pure C99 and demonstrates the use of
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// the C API to the CLBlast library.
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//
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// Note that this example is meant for illustration purposes only. CLBlast provides other programs
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// for performance benchmarking ('client_xxxxx') and for correctness testing ('test_xxxxx').
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//
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// =================================================================================================
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#define CL_TARGET_OPENCL_VERSION 120
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#define CL_USE_DEPRECATED_OPENCL_1_2_APIS // to disable deprecation warnings
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// Includes the CLBlast library (C interface)
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#include <clblast_c.h>
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// =================================================================================================
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// Example use of the single-precision routine iSAMAX
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int main(void) {
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// OpenCL platform/device settings
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const size_t platform_id = 0;
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const size_t device_id = 0;
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// Example iSAMAX arguments
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const size_t n = 1000;
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// Initializes the OpenCL platform
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cl_uint num_platforms;
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clGetPlatformIDs(0, NULL, &num_platforms);
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cl_platform_id* platforms = (cl_platform_id*)malloc(num_platforms*sizeof(cl_platform_id));
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clGetPlatformIDs(num_platforms, platforms, NULL);
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cl_platform_id platform = platforms[platform_id];
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// Initializes the OpenCL device
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cl_uint num_devices;
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clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 0, NULL, &num_devices);
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cl_device_id* devices = (cl_device_id*)malloc(num_devices*sizeof(cl_device_id));
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clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, num_devices, devices, NULL);
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cl_device_id device = devices[device_id];
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// Creates the OpenCL context, queue, and an event
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cl_context context = clCreateContext(NULL, 1, &device, NULL, NULL, NULL);
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cl_command_queue queue = clCreateCommandQueue(context, device, 0, NULL);
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cl_event event = NULL;
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// Populate host data structures with some example data
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float* host_input = (float*)malloc(sizeof(float)*n);
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unsigned int* host_output = (unsigned int*)malloc(sizeof(unsigned int)*1);
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for (size_t i=0; i<n; ++i) { host_input[i] = (float)(i % 10); } // staircase modulo 10
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for (size_t i=0; i<1; ++i) { host_output[i] = 77; } // some temp value to be overwritten later
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// Copy the data-structures to the device
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cl_mem device_input = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(float), NULL, NULL);
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cl_mem device_output = clCreateBuffer(context, CL_MEM_READ_WRITE, 1*sizeof(unsigned int), NULL, NULL);
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clEnqueueWriteBuffer(queue, device_input, CL_TRUE, 0, n*sizeof(float), host_input, 0, NULL, NULL);
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clEnqueueWriteBuffer(queue, device_output, CL_TRUE, 0, 1*sizeof(unsigned int), host_output, 0, NULL, NULL);
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// Call the iSAMAX routine.
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CLBlastStatusCode status = CLBlastiSamax(n,
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device_output, 0,
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device_input, 0, 1,
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&queue, &event);
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// Wait for completion
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if (status == CLBlastSuccess) {
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clWaitForEvents(1, &event);
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clReleaseEvent(event);
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}
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// Copies the result back to the host
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clEnqueueReadBuffer(queue, device_output, CL_TRUE, 0, 1*sizeof(unsigned int), host_output, 0, NULL, NULL);
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// Example completed. See "clblast_c.h" for status codes (0 -> success).
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printf("Completed iSAMAX with status %d: array of %zu values with staircases from 0..9 repeated, max at index %u with value %.0lf\n",
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status, n, host_output[0], host_input[host_output[0]]);
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// Clean-up
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free(platforms);
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free(devices);
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free(host_input);
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free(host_output);
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clReleaseMemObject(device_input);
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clReleaseMemObject(device_output);
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clReleaseCommandQueue(queue);
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clReleaseContext(context);
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return 0;
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}
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// =================================================================================================
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