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→Final version's errors, warnings and observations
==== Conclusion: Logical Error ====
[[Image:gpuA3error.png|thumb|widthpx| ]]
The prime number generated seems to have run into some logical error. It does not generate the prime numbers correctly. Instead spits out all numbers.
Gives a run time error "invalid argument". Logical error still persists.
==== Final Cuda version ====<pre>#include <cstdio>#include <cstdlib>#include <iostream>#include <ctime>#include <cuda_runtime.h> using namespace std; /** * This macro checks return value of the CUDA runtime call and exits * the application if the call failed. */#define CUDA_CHECK_RETURN(value) { \ cudaError_t _m_cudaStat = value; \ if (_m_cudaStat != cudaSuccess) { \ fprintf(stderr, "Error %s at line %d in file %s\n", \ cudaGetErrorString(_m_cudaStat), __LINE__, __FILE__); \ exit(1); \ } } /** * Kernel code to generate and detect primes */__global__ void prime(int *num, int blockNum, int threadNum, int size) { const int tid = blockIdx.x * blockDim.x + threadIdx.x; const int bid = blockIdx.y * blockDim.y + threadIdx.y; __syncthreads(); /** * Generate prime numbers and store them in the array. * The first element is always 2 */ if(tid == 0) { num[tid] = 2; } else { num[tid] = 2 * tid + 1; } int tmp = bid * threadNum + tid; int step1 = 2 * tmp + 3; int step2 = tmp + 1; while(tmp < size) { int i = 1; /** * Check if an element is not prime, if it isn't set it to 0. */ while((step1 * i + step2) < size) { num[step1 * i + step2] = 0; i++; } tmp += blockNum * threadNum; __syncthreads(); }} int main(int argc, char* argv[]) { if(argc != 2) { cout << "Incorrect no of arguments" << endl; return 1; } int n = atoi(argv[1]); /** * variable declarations */ int *device; int host[n]; int d; cudaDeviceProp prop; /** * Get the properties of the device in use */ cudaGetDevice(&d); cudaGetDeviceProperties(&prop, d); int numberOfBlocks = 8; int maxThreadsPerBlock = prop.maxThreadsPerBlock; int numberOfThreads = maxThreadsPerBlock/numberOfBlocks; /** * Start timer */ clock_t cb, ce; cb = clock(); /** * Allocate memory on the device */ CUDA_CHECK_RETURN(cudaMalloc((void**) &device, sizeof(int) * n)); /** * Call kernel with appropriate grid and thread size */ prime<<<numberOfBlocks, numberOfThreads>>>(device, numberOfBlocks, numberOfThreads, n); /** * Copy results back to host */ CUDA_CHECK_RETURN(cudaMemcpy(&host, device, sizeof(int) * n, cudaMemcpyDeviceToHost)); /** * Free memory on device */ CUDA_CHECK_RETURN(cudaFree(device)); /** * Output values */ for (int i = 0; i < n; i++) if (host[i] != 0) cout << host[i] << endl; /** * Stop timer */ ce = clock(); cout << "Prime generation - took " << double(ce - cb)/CLOCKS_PER_SEC << " seconds" << endl;}</pre>[[Image:gpuA3errormanualDelete.png|thumb|widthpx200px| Manual Delete Warning]]===== Final version's errors, warnings and observations =====* If a number over 515 is entered as the launch argument, the program will display random values at the end of the list of prime numbers* When attempting to delete the host array manually in the program, a warning is displayed[[Image:ManualCrash.png|thumb|200px|Manual Delete Crash]]* The program crashes at the end if the host array is manually deleted ===== Successful run of Prime generation =====[[Image:PrimeSuccessfulRun.png]]
