143 lines
4.9 KiB
C
143 lines
4.9 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <clFFT.h>
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const char *kernelSource =
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"#pragma OPENCL EXTENSION cl_khr_fp64 : enable \n" \
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"__kernel void mult(__global double *vR, __global double *vI) { \n" \
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" int id; \n" \
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" id = get_global_id(0); \n" \
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" vR[id] = 2*vR[id]; \n" \
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" vI[id] = 2*vI[id]; \n" \
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"} \n" \
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"\n" ;
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int main( int argc, char* argv[] ) {
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// problem-related declarations
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unsigned int N = 128;
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size_t N_bytes = N * sizeof(double);
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// openCL declarations
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cl_platform_id platform;
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cl_device_id device_id;
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cl_context context;
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cl_command_queue queue;
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cl_program program;
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cl_kernel k_mult;
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// clFFT declarations
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clfftPlanHandle planHandleForward, planHandleBackward;
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clfftDim dim = CLFFT_1D;
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size_t clLengths[1] = {N};
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clfftSetupData fftSetup;
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clfftInitSetupData(&fftSetup);
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clfftSetup(&fftSetup);
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// host version of v
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double *h_vR, *h_vI; // real & imaginary parts
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h_vR = (double*) malloc(N_bytes);
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h_vI = (double*) malloc(N_bytes);
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// initialize v on host
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int i;
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for (i = 0; i < N; i++) {
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h_vR[i] = i;
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h_vI[i] = 2*i;
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}
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// global & local number of threads
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size_t globalSize, localSize;
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globalSize = N;
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localSize = 32;
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// setup OpenCL stuff
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cl_int err;
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err = clGetPlatformIDs(1, &platform, NULL);
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err = clGetDeviceIDs(platform, CL_DEVICE_TYPE_GPU, 1, &device_id, NULL);
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context = clCreateContext(0, 1, &device_id, NULL, NULL, &err);
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queue = clCreateCommandQueue(context, device_id, 0, &err);
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program = clCreateProgramWithSource(context, 1, (const char **) & kernelSource, NULL, &err);
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// Build the program executable
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err = clBuildProgram(program, 0, NULL, NULL, NULL, NULL);
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if (err != CL_SUCCESS) {
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printf("building program failed\n");
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if (err == CL_BUILD_PROGRAM_FAILURE) {
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size_t log_size;
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clGetProgramBuildInfo(program, device_id, CL_PROGRAM_BUILD_LOG, 0, NULL, &log_size);
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char *log = (char *) malloc(log_size);
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clGetProgramBuildInfo(program, device_id, CL_PROGRAM_BUILD_LOG, log_size, log, NULL);
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printf("%s\n", log);
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}
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}
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k_mult = clCreateKernel(program, "mult", &err);
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// create arrays on host and write them
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cl_mem d_vR, d_vI;
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d_vR = clCreateBuffer(context, CL_MEM_READ_WRITE, N_bytes, NULL, NULL);
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d_vI = clCreateBuffer(context, CL_MEM_READ_WRITE, N_bytes, NULL, NULL);
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err = clEnqueueWriteBuffer(queue, d_vR, CL_TRUE, 0, N_bytes, h_vR, 0, NULL, NULL);
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err |= clEnqueueWriteBuffer(queue, d_vI, CL_TRUE, 0, N_bytes, h_vI, 0, NULL, NULL);
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// create forward plan and set its params
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clfftCreateDefaultPlan(&planHandleForward, context, dim, clLengths);
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clfftSetPlanPrecision(planHandleForward, CLFFT_DOUBLE);
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clfftSetLayout(planHandleForward, CLFFT_COMPLEX_PLANAR, CLFFT_COMPLEX_PLANAR);
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clfftSetResultLocation(planHandleForward, CLFFT_INPLACE);
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clfftBakePlan(planHandleForward, 1, &queue, NULL, NULL);
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// create backward plan and set its params
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clfftCreateDefaultPlan(&planHandleBackward, context, dim, clLengths);
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clfftSetPlanPrecision(planHandleBackward, CLFFT_DOUBLE);
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clfftSetLayout(planHandleBackward, CLFFT_COMPLEX_PLANAR, CLFFT_COMPLEX_PLANAR);
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clfftSetResultLocation(planHandleBackward, CLFFT_INPLACE);
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clfftBakePlan(planHandleBackward, 1, &queue, NULL, NULL);
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// set all of ze kernel args...
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err = clSetKernelArg(k_mult, 0, sizeof(cl_mem), &d_vR);
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err |= clSetKernelArg(k_mult, 1, sizeof(cl_mem), &d_vI);
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// cl_mem array allows for complex_planar transform
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cl_mem inputBuffers[2] = {0, 0};
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inputBuffers[0] = d_vR;
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inputBuffers[1] = d_vI;
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// FFT data, apply psi, IFFT data
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clfftEnqueueTransform(planHandleForward, CLFFT_FORWARD, 1, &queue, 0, NULL, NULL, &inputBuffers, NULL, NULL);
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clFinish(queue);
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err = clEnqueueNDRangeKernel(queue, k_mult, 1, NULL, &globalSize, &localSize, 0, NULL, NULL);
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clfftEnqueueTransform(planHandleBackward, CLFFT_BACKWARD, 1, &queue, 0, NULL, NULL, &inputBuffers, NULL, NULL);
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// transfer back
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clEnqueueReadBuffer(queue, d_vR, CL_TRUE, 0, N_bytes, h_vR, 0, NULL, NULL );
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clEnqueueReadBuffer(queue, d_vI, CL_TRUE, 0, N_bytes, h_vI, 0, NULL, NULL );
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clFinish(queue);
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printf("[ ");
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for (i=0; i<N; i++)
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printf("(%f, %f) ", h_vR[i], h_vI[i]);
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printf("]\n");
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// release clFFT stuff
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clfftDestroyPlan( &planHandleForward );
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clfftDestroyPlan( &planHandleBackward );
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clfftTeardown();
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// release OpenCL resources
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clReleaseMemObject(d_vR);
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clReleaseMemObject(d_vI);
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clReleaseProgram(program);
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clReleaseKernel(k_mult);
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clReleaseCommandQueue(queue);
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clReleaseContext(context);
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//release host memory
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free(h_vR);
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free(h_vI);
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return 0;
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}
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