/usr/include/ngram/ngram-kneser-ney.h is in libngram-dev 1.3.2-3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | // Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Copyright 2005-2016 Brian Roark and Google, Inc.
// Kneser-Ney derived class for smoothing.
#ifndef NGRAM_NGRAM_KNESER_NEY_H_
#define NGRAM_NGRAM_KNESER_NEY_H_
#include <vector>
#include <ngram/ngram-absolute.h>
namespace ngram {
class NGramKneserNey : public NGramAbsolute {
public:
// Construct NGramKneserNey object, consisting of the FST and some
// information about the states under the assumption that the FST is a model.
// Ownership of the FST is retained by the caller.
explicit NGramKneserNey(StdMutableFst *infst, bool backoff = false,
Label backoff_label = 0, double norm_eps = kNormEps,
bool check_consistency = false,
double parameter = -1.0, int bins = -1)
: NGramAbsolute(infst, backoff, backoff_label, norm_eps,
check_consistency, parameter, bins) {}
// Smooth model according to 'method' and parameters.
bool MakeNGramModel();
private:
// Update arc and final values, either initializing or incrementing
bool UpdateKneserNeyCounts(StateId st, bool increment);
// Calculate update value, either for incrementing or removing hi order
double CalcKNValue(bool increment, double hi_order_value,
double lo_order_value);
// Update the backoff arc with total count
bool UpdateTotalCount(StateId st);
// Modify lower order counts according to Kneser Ney formula
void AssignKneserNeyCounts();
};
} // namespace ngram
#endif // NGRAM_NGRAM_KNESER_NEY_H_
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