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example_device_radix_sort.cu
/******************************************************************************
* Copyright (c) 2011, Duane Merrill. All rights reserved.
* Copyright (c) 2011-2018, NVIDIA CORPORATION. All rights reserved.
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/******************************************************************************
* Simple example of DeviceRadixSort::SortPairs().
*
* Sorts an array of float keys paired with a corresponding array of int values.
*
* To compile using the command line:
* nvcc -arch=sm_XX example_device_radix_sort.cu -I../.. -lcudart -O3
*
******************************************************************************/
// Ensure printing of CUDA runtime errors to console
#define CUB_STDERR
#include <stdio.h>
#include <algorithm>
#include <cub/util_allocator.cuh>
#include "../../test/test_util.h"
using namespace cub;
//---------------------------------------------------------------------
// Globals, constants and typedefs
//---------------------------------------------------------------------
bool g_verbose = false; // Whether to display input/output to console
CachingDeviceAllocator g_allocator(true); // Caching allocator for device memory
//---------------------------------------------------------------------
// Test generation
//---------------------------------------------------------------------
struct Pair
{
float key;
int value;
bool operator<(const Pair &b) const
{
if (key < b.key)
return true;
if (key > b.key)
return false;
// Return true if key is negative zero and b.key is positive zero
unsigned int key_bits = *reinterpret_cast<unsigned*>(const_cast<float*>(&key));
unsigned int b_key_bits = *reinterpret_cast<unsigned*>(const_cast<float*>(&b.key));
unsigned int HIGH_BIT = 1u << 31;
return ((key_bits & HIGH_BIT) != 0) && ((b_key_bits & HIGH_BIT) == 0);
}
};
void Initialize(
float *h_keys,
int *h_values,
float *h_reference_keys,
int *h_reference_values,
int num_items)
{
Pair *h_pairs = new Pair[num_items];
for (int i = 0; i < num_items; ++i)
{
RandomBits(h_keys[i]);
RandomBits(h_values[i]);
h_pairs[i].key = h_keys[i];
h_pairs[i].value = h_values[i];
}
if (g_verbose)
{
printf("Input keys:\n");
DisplayResults(h_keys, num_items);
printf("\n\n");
printf("Input values:\n");
DisplayResults(h_values, num_items);
printf("\n\n");
}
std::stable_sort(h_pairs, h_pairs + num_items);
for (int i = 0; i < num_items; ++i)
{
h_reference_keys[i] = h_pairs[i].key;
h_reference_values[i] = h_pairs[i].value;
}
delete[] h_pairs;
}
//---------------------------------------------------------------------
// Main
//---------------------------------------------------------------------
int main(int argc, char** argv)
{
int num_items = 150;
// Initialize command line
CommandLineArgs args(argc, argv);
g_verbose = args.CheckCmdLineFlag("v");
args.GetCmdLineArgument("n", num_items);
// Print usage
if (args.CheckCmdLineFlag("help"))
{
printf("%s "
"[--n=<input items> "
"[--device=<device-id>] "
"[--v] "
"\n", argv[0]);
exit(0);
}
// Initialize device
CubDebugExit(args.DeviceInit());
printf("cub::DeviceRadixSort::SortPairs() %d items (%d-byte keys %d-byte values)\n",
num_items, int(sizeof(float)), int(sizeof(int)));
fflush(stdout);
// Allocate host arrays
float *h_keys = new float[num_items];
float *h_reference_keys = new float[num_items];
int *h_values = new int[num_items];
int *h_reference_values = new int[num_items];
// Initialize problem and solution on host
Initialize(h_keys, h_values, h_reference_keys, h_reference_values, num_items);
// Allocate device arrays
DoubleBuffer<float> d_keys;
DoubleBuffer<int> d_values;
CubDebugExit(g_allocator.DeviceAllocate((void**)&d_keys.d_buffers[0], sizeof(float) * num_items));
CubDebugExit(g_allocator.DeviceAllocate((void**)&d_keys.d_buffers[1], sizeof(float) * num_items));
CubDebugExit(g_allocator.DeviceAllocate((void**)&d_values.d_buffers[0], sizeof(int) * num_items));
CubDebugExit(g_allocator.DeviceAllocate((void**)&d_values.d_buffers[1], sizeof(int) * num_items));
// Allocate temporary storage
size_t temp_storage_bytes = 0;
void *d_temp_storage = NULL;
CubDebugExit(DeviceRadixSort::SortPairs(d_temp_storage, temp_storage_bytes, d_keys, d_values, num_items));
CubDebugExit(g_allocator.DeviceAllocate(&d_temp_storage, temp_storage_bytes));
// Initialize device arrays
CubDebugExit(cudaMemcpy(d_keys.d_buffers[d_keys.selector], h_keys, sizeof(float) * num_items, cudaMemcpyHostToDevice));
CubDebugExit(cudaMemcpy(d_values.d_buffers[d_values.selector], h_values, sizeof(int) * num_items, cudaMemcpyHostToDevice));
// Run
CubDebugExit(DeviceRadixSort::SortPairs(d_temp_storage, temp_storage_bytes, d_keys, d_values, num_items));
// Check for correctness (and display results, if specified)
int compare = CompareDeviceResults(h_reference_keys, d_keys.Current(), num_items, true, g_verbose);
printf("\t Compare keys (selector %d): %s\n", d_keys.selector, compare ? "FAIL" : "PASS");
AssertEquals(0, compare);
compare = CompareDeviceResults(h_reference_values, d_values.Current(), num_items, true, g_verbose);
printf("\t Compare values (selector %d): %s\n", d_values.selector, compare ? "FAIL" : "PASS");
AssertEquals(0, compare);
// Cleanup
if (h_keys) delete[] h_keys;
if (h_reference_keys) delete[] h_reference_keys;
if (h_values) delete[] h_values;
if (h_reference_values) delete[] h_reference_values;
if (d_keys.d_buffers[0]) CubDebugExit(g_allocator.DeviceFree(d_keys.d_buffers[0]));
if (d_keys.d_buffers[1]) CubDebugExit(g_allocator.DeviceFree(d_keys.d_buffers[1]));
if (d_values.d_buffers[0]) CubDebugExit(g_allocator.DeviceFree(d_values.d_buffers[0]));
if (d_values.d_buffers[1]) CubDebugExit(g_allocator.DeviceFree(d_values.d_buffers[1]));
if (d_temp_storage) CubDebugExit(g_allocator.DeviceFree(d_temp_storage));
printf("\n\n");
return 0;
}