100 lines
2.8 KiB
C++
100 lines
2.8 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <iterator>
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#ifdef __APPLE__
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#include <OpenCL/cl.hpp>
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#else
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#include <CL/cl.hpp>
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#endif
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using namespace std;
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using namespace cl;
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int factorial(int n) {
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return (n <= 1) ? 1 : n * factorial(n-1);
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}
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Platform getPlatform() {
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/* Returns the first platform found. */
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std::vector<Platform> all_platforms;
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Platform::get(&all_platforms);
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if (all_platforms.size()==0) {
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cout << "No platforms found. Check OpenCL installation!\n";
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exit(1);
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}
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return all_platforms[0];
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}
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Device getDevice(Platform platform, int i, bool display=false) {
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/* Returns the deviced specified by the index i on platform.
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* If display is true, then all of the platforms are listed.
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*/
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std::vector<Device> all_devices;
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platform.getDevices(CL_DEVICE_TYPE_ALL, &all_devices);
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if(all_devices.size()==0){
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cout << "No devices found. Check OpenCL installation!\n";
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exit(1);
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}
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if (display) {
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for (int j=0; j<all_devices.size(); j++)
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printf("Device %d: %s\n", j, all_devices[j].getInfo<CL_DEVICE_NAME>().c_str());
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}
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return all_devices[i];
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}
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int main() {
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const int n = 1024; // size of vectors
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const int c_max = 5; // max value to iterate to
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const int coeff = factorial(c_max);
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int A[n], B[n], C[n]; // A is initial, B is result, C is expected result
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for (int i=0; i<n; i++) {
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A[i] = i;
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C[i] = coeff * i;
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}
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Platform default_platform = getPlatform();
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Device default_device = getDevice(default_platform, 1);
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Context context({default_device});
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Program::Sources sources;
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std::string kernel_code=
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"void kernel multiply_by(global int* A, const int c) {"
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" A[get_global_id(0)] = c * A[get_global_id(0)];"
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"}";
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sources.push_back({kernel_code.c_str(), kernel_code.length()});
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Program program(context, sources);
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if (program.build({default_device}) != CL_SUCCESS) {
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cout << "Error building: " << program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(default_device) << std::endl;
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exit(1);
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}
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Buffer buffer_A(context, CL_MEM_READ_WRITE, sizeof(int) * n);
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CommandQueue queue(context, default_device);
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queue.enqueueWriteBuffer(buffer_A, CL_TRUE, 0, sizeof(int)*n, A);
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Kernel multiply_by = Kernel(program, "multiply_by");
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multiply_by.setArg(0, buffer_A);
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for (int c=2; c<=c_max; c++) {
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multiply_by.setArg(1, c);
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queue.enqueueNDRangeKernel(multiply_by, NullRange, NDRange(n), NDRange(32));
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}
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queue.enqueueReadBuffer(buffer_A, CL_TRUE, 0, sizeof(int)*n, B);
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if (std::equal(std::begin(B), std::end(B), std::begin(C)))
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cout << "Arrays are equal!" << endl;
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else
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cout << "Uh-oh, the arrays aren't equal!" << endl;
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return 0;
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}
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