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improved comments.

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This commit is contained in:
Dan 2015-09-24 09:19:37 -04:00
parent 23fc5930b7
commit 00c2930709
1 changed files with 16 additions and 10 deletions
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26
samples/cpp/tutorial_code/gpu/gpu-thrust-interop/main.cu
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@ -45,19 +45,21 @@ int main(void)
// generated value. Sort by the randomly generated value while maintaining index association.
//! [sort]
{
cv::cuda::GpuMat d_idx(1, 100, CV_32SC2);
auto keyBegin = GpuMatBeginItr<int>(d_idx, 1);
auto keyEnd = GpuMatEndItr<int>(d_idx, 1);
auto idxBegin = GpuMatBeginItr<int>(d_idx, 0);
auto idxEnd = GpuMatEndItr<int>(d_idx, 0);
cv::cuda::GpuMat d_data(1, 100, CV_32SC2);
// Thrust compatible begin and end iterators to channel 1 of this matrix
auto keyBegin = GpuMatBeginItr<int>(d_data, 1);
auto keyEnd = GpuMatEndItr<int>(d_data, 1);
// Thrust compatible begin and end iterators to channel 0 of this matrix
auto idxBegin = GpuMatBeginItr<int>(d_data, 0);
auto idxEnd = GpuMatEndItr<int>(d_data, 0);
// Fill the index channel with a sequence of numbers from 0 to 100
thrust::sequence(idxBegin, idxEnd);
thrust::transform(idxBegin, idxEnd, keyBegin, prg(0, 10));
// Fill the key channel with random numbers between 0 and 10. A counting iterator is used here to give an integer value for each location as an input to prg::operator()
thrust::transform(thrust::make_counting_iterator(0), thrust::make_counting_iterator(d_data.cols), keyBegin, prg(0, 10));
// Sort the key channel and index channel such that the keys and indecies stay together
thrust::sort_by_key(keyBegin, keyEnd, idxBegin);
cv::Mat h_idx(d_idx);
cv::Mat h_idx(d_data);
}
//! [sort]
@ -92,10 +94,14 @@ int main(void)
auto valueEnd = GpuMatEndItr<float>(d_value);
cv::cuda::Stream stream;
//! [random_gen_stream]
// Same as the random generation code from before except now the transformation is being performed on a stream
thrust::transform(thrust::system::cuda::par.on(cv::cuda::StreamAccessor::getStream(stream)), thrust::make_counting_iterator(0), thrust::make_counting_iterator(d_value.cols), valueBegin, prg(-1, 1));
//! [random_gen_stream]
// Count the number of values we are going to copy
int count = thrust::count_if(thrust::system::cuda::par.on(cv::cuda::StreamAccessor::getStream(stream)), valueBegin, valueEnd, pred_greater<float>(0.0));
// Allocate a destination for copied values
cv::cuda::GpuMat d_valueGreater(1, count, CV_32F);
// Copy values that satisfy the predicate.
thrust::copy_if(thrust::system::cuda::par.on(cv::cuda::StreamAccessor::getStream(stream)), valueBegin, valueEnd, GpuMatBeginItr<float>(d_valueGreater), pred_greater<float>(0.0));
cv::Mat h_greater(d_valueGreater);
}