Add BitFlip and Sometimes Emission classes #46
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| bool propose_clean(const std::vector<bool>& corrupted, | ||
| std::mt19937* unused_prng) { | ||
| return !corrupted[0]; |
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I don't entirely understand how propose_clean will be used, but would it be better to choose a random element of corrupted to invert? Or is corrupted expected to contain all the same values?
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corrupted is expected to contain all the same values. Specifically, the contract for the corrupted vector is that it is the output of sample_corrupted over repeated calls with the same clean value.
cxx/emissions/sometimes.hh
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| // We approximate the maximum likelihood estimate by taking the mode of | ||
| // corrupted. The full solution would construct BaseEmissor and | ||
| // BetaBernoulli instances for each choice of clean and picking the | ||
| // clean with the lowest combined logp_score(). |
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Should this be "highest" instead of "lowest"?
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Yes! Fixed.
| int max_count = 0; | ||
| for (const SampleType& c: corrupted) { | ||
| ++counts[c]; | ||
| if (counts[c] > max_count) { |
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Optional nit: it seems cleaner to me to do this after the loop terminates with std::max_element.
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I considered that, but the code to use std::max_element over a map turns out to be many lines that look ugly to me:
auto max = std::max_element(
std::begin(counts), std::end(counts),
[] (const auto &p1, const auto &p2) { return p1.second < p2.second; }
)
return max->first;
| Sometimes() : bb(nullptr) {}; | ||
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| void incorporate(const std::pair<SampleType, SampleType>& x) { | ||
| ++(this->N); |
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For my own understanding, how come N is accessed by pointer here and not in the other Emission subclasses?
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I really really wish I knew. I originally had it as ++N; and the compiler complained that no variable named N was defined in scope.
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