main.cpp

#include "bitonic_sort.cuh"
#include <cuda_runtime.h>
#include <stdio.h>
#include <stdlib.h>

// Function to check if the array is sorted
bool isSorted(int *arr, int size) {
  for (int i = 1; i < size; i++) {
    if (arr[i] < arr[i - 1])
      return false;
  }
  return true;
}

int main() {
  const int SIZE = 1048576; // Must be a multiple of 32 for this example

  // Allocate and initialize host array
  int *h_arr = new int[SIZE];
  for (int i = 0; i < SIZE; i++) {
    h_arr[i] = rand() % 1000; // Random integers between 0 and 999
  }

  // Allocate device array
  int *d_arr;
  cudaMalloc(&d_arr, SIZE * sizeof(int));

  // Copy host array to device
  cudaMemcpy(d_arr, h_arr, SIZE * sizeof(int), cudaMemcpyHostToDevice);

  // Create CUDA events for timing
  cudaEvent_t start, stop;
  cudaEventCreate(&start);
  cudaEventCreate(&stop);

  // Record the start event
  cudaEventRecord(start, nullptr);

  // Launch kernel
  launchBitonicSort(d_arr, SIZE);

  // Record the stop event
  cudaEventRecord(stop, nullptr);
  cudaEventSynchronize(stop);

  // Calculate elapsed time
  float milliseconds = 0;
  cudaEventElapsedTime(&milliseconds, start, stop);

  // Copy result back to host
  cudaMemcpy(h_arr, d_arr, SIZE * sizeof(int), cudaMemcpyDeviceToHost);

  // Check if sorted
  bool sorted = isSorted(h_arr, SIZE);
  printf("Array is %s\n", sorted ? "sorted" : "not sorted");

  // Print first few elements to verify
  printf("First 32 elements: ");
  for (int i = 0; i < 32; i++) {
    printf("%d ", h_arr[i]);
  }
  printf("\n");

  // Print timing information
  printf("Kernel execution time: %f milliseconds\n", milliseconds);

  // Clean up
  delete[] h_arr;
  cudaFree(d_arr);
  cudaEventDestroy(start);
  cudaEventDestroy(stop);

  return 0;
}