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/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of NVIDIA CORPORATION nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <thrust/device_ptr.h>
#include <thrust/count.h>
#include <thrust/execution_policy.h>
#include <iostream>
#include <helper_cuda.h>
/////////////////////////////////////////////////////////////////
// Some utility code to define grid_stride_range
// Normally this would be in a header but it's here
// for didactic purposes. Uses
#include "range.hpp"
using namespace util::lang;
// type alias to simplify typing...
template <typename T>
using step_range = typename range_proxy<T>::step_range_proxy;
template <typename T>
__device__ step_range<T> grid_stride_range(T begin, T end) {
begin += blockDim.x * blockIdx.x + threadIdx.x;
return range(begin, end).step(gridDim.x * blockDim.x);
}
/////////////////////////////////////////////////////////////////
template <typename T, typename Predicate>
__device__ void count_if(int *count, T *data, int n, Predicate p) {
for (auto i : grid_stride_range(0, n)) {
if (p(data[i])) atomicAdd(count, 1);
}
}
// Use count_if with a lambda function that searches for x, y, z or w
// Note the use of range-based for loop and initializer_list inside the functor
// We use auto so we don't have to know the type of the functor or array
__global__ void xyzw_frequency(int *count, char *text, int n) {
const char letters[]{'x', 'y', 'z', 'w'};
count_if(count, text, n, [&](char c) {
for (const auto x : letters)
if (c == x) return true;
return false;
});
}
__global__ void xyzw_frequency_thrust_device(int *count, char *text, int n) {
const char letters[]{'x', 'y', 'z', 'w'};
*count = thrust::count_if(thrust::device, text, text + n, [=](char c) {
for (const auto x : letters)
if (c == x) return true;
return false;
});
}
// a bug in Thrust 1.8 causes warnings when this is uncommented
// so commented out by default -- fixed in Thrust master branch
#if 0
void xyzw_frequency_thrust_host(int *count, char *text, int n)
{
const char letters[] { 'x','y','z','w' };
*count = thrust::count_if(thrust::host, text, text+n, [&](char c) {
for (const auto x : letters)
if (c == x) return true;
return false;
});
}
#endif
int main(int argc, char **argv) {
const char *filename = sdkFindFilePath("warandpeace.txt", argv[0]);
int numBytes = 16 * 1048576;
char *h_text = (char *)malloc(numBytes);
// find first CUDA device
int devID = findCudaDevice(argc, (const char **)argv);
char *d_text;
checkCudaErrors(cudaMalloc((void **)&d_text, numBytes));
FILE *fp = fopen(filename, "r");
if (fp == NULL) {
printf("Cannot find the input text file\n. Exiting..\n");
return EXIT_FAILURE;
}
int len = (int)fread(h_text, sizeof(char), numBytes, fp);
fclose(fp);
std::cout << "Read " << len << " byte corpus from " << filename << std::endl;
checkCudaErrors(cudaMemcpy(d_text, h_text, len, cudaMemcpyHostToDevice));
int count = 0;
int *d_count;
checkCudaErrors(cudaMalloc(&d_count, sizeof(int)));
checkCudaErrors(cudaMemset(d_count, 0, sizeof(int)));
// Try uncommenting one kernel call at a time
xyzw_frequency<<<8, 256>>>(d_count, d_text, len);
xyzw_frequency_thrust_device<<<1, 1>>>(d_count, d_text, len);
checkCudaErrors(
cudaMemcpy(&count, d_count, sizeof(int), cudaMemcpyDeviceToHost));
// xyzw_frequency_thrust_host(&count, h_text, len);
std::cout << "counted " << count
<< " instances of 'x', 'y', 'z', or 'w' in \"" << filename << "\""
<< std::endl;
checkCudaErrors(cudaFree(d_count));
checkCudaErrors(cudaFree(d_text));
return EXIT_SUCCESS;
}
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