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178676df4f
This refactors the system::default_device() method. Now, the default compute device for the system is only found once and stored in a static variable. This eliminates many redundant calls to clGetPlatformIDs() and clGetDeviceIDs(). Also, the default_cpu_device() and default_gpu_device() methods have been removed and their usages replaced with default_device().
83 lines
2.5 KiB
C++
83 lines
2.5 KiB
C++
//---------------------------------------------------------------------------//
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// Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://kylelutz.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#include <iostream>
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#include <boost/compute.hpp>
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// this example demonstrates how to use the Boost.Compute classes to
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// setup and run a simple vector addition kernel on the GPU
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int main()
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{
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// get the default device
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boost::compute::device gpu =
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boost::compute::system::default_device();
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// create a context for the device
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boost::compute::context context(gpu);
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// setup input arrays
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float a[] = { 1, 2, 3, 4 };
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float b[] = { 5, 6, 7, 8 };
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// make space for the output
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float c[] = { 0, 0, 0, 0 };
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// create memory buffers for the input and output
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boost::compute::buffer buffer_a(context, 4 * sizeof(float));
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boost::compute::buffer buffer_b(context, 4 * sizeof(float));
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boost::compute::buffer buffer_c(context, 4 * sizeof(float));
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// source code for the add kernel
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const char source[] =
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"__kernel void add(__global const float *a,"
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" __global const float *b,"
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" __global float *c)"
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"{"
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" const uint i = get_global_id(0);"
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" c[i] = a[i] + b[i];"
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"}";
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// create the program with the source
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boost::compute::program program =
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boost::compute::program::create_with_source(source, context);
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// compile the program
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program.build();
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// create the kernel
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boost::compute::kernel kernel(program, "add");
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// set the kernel arguments
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kernel.set_arg(0, buffer_a);
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kernel.set_arg(1, buffer_b);
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kernel.set_arg(2, buffer_c);
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// create a command queue
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boost::compute::command_queue queue(context, gpu);
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// write the data from 'a' and 'b' to the device
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queue.enqueue_write_buffer(buffer_a, a);
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queue.enqueue_write_buffer(buffer_b, b);
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// run the add kernel
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queue.enqueue_1d_range_kernel(kernel, 0, 4);
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// transfer results back to the host array 'c'
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queue.enqueue_read_buffer(buffer_c, c);
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// print out results in 'c'
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std::cout << "c: [" << c[0] << ", "
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<< c[1] << ", "
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<< c[2] << ", "
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<< c[3] << "]" << std::endl;
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return 0;
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}
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