35 lines
1.1 KiB
Plaintext
35 lines
1.1 KiB
Plaintext
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#include <thrust/copy.h>
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#include <thrust/device_vector.h>
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#include <thrust/functional.h>
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#include <thrust/iterator/counting_iterator.h>
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#include <iostream>
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#include <iterator>
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int main()
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{
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// this example computes indices for all the nonzero values in a sequence
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// sequence of zero and nonzero values
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thrust::device_vector<int> stencil{0, 1, 1, 0, 0, 1, 0, 1};
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// storage for the nonzero indices
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thrust::device_vector<int> indices(8);
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// counting iterators define a sequence [0, 8)
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thrust::counting_iterator<int> first(0);
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thrust::counting_iterator<int> last = first + 8;
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// compute indices of nonzero elements
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using IndexIterator = thrust::device_vector<int>::iterator;
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IndexIterator indices_end = thrust::copy_if(first, last, stencil.begin(), indices.begin(), cuda::std::identity{});
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// indices now contains [1,2,5,7]
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// print result
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std::cout << "found " << cuda::std::distance(indices.begin(), indices_end) << " nonzero values at indices:\n";
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thrust::copy(indices.begin(), indices_end, std::ostream_iterator<int>(std::cout, "\n"));
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return 0;
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}
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