33 lines
1017 B
C
33 lines
1017 B
C
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#ifndef VTR_RANDOM_H
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#define VTR_RANDOM_H
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#include <algorithm> //For std::swap
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namespace vtr {
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/*********************** Portable random number generators *******************/
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typedef unsigned RandState;
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void srandom(int seed);
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RandState get_random_state();
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int irand(int imax);
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int irand(int imax, RandState& rand_state);
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float frand();
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//Portable/invariant version of std::shuffle
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//
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//Note that std::shuffle relies on std::uniform_int_distribution
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//which can produce different sequences accross different
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//compilers/compiler versions.
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//
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//This version should be deterministic/invariant. However, since
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//it uses vtr::irand(), may not be as well distributed as std::shuffle.
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template<typename Iter>
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void shuffle(Iter first, Iter last, RandState& rand_state) {
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for (auto i = (last - first) - 1; i > 0; --i) {
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using std::swap;
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swap(first[i], first[irand(i, rand_state)]);
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}
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}
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} //namespace
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#endif
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