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#ifndef LM_QUANTIZE_H__
#define LM_QUANTIZE_H__
#include "lm/blank.hh"
#include "lm/config.hh"
#include "lm/max_order.hh"
#include "lm/model_type.hh"
#include "util/bit_packing.hh"
#include <algorithm>
#include <vector>
#include <stdint.h>
#include <iostream>
namespace lm {
namespace ngram {
struct Config;
/* Store values directly and don't quantize. */
class DontQuantize {
public:
static const ModelType kModelTypeAdd = static_cast<ModelType>(0);
static void UpdateConfigFromBinary(int, const std::vector<uint64_t> &, Config &) {}
static std::size_t Size(uint8_t /*order*/, const Config &/*config*/) { return 0; }
static uint8_t MiddleBits(const Config &/*config*/) { return 63; }
static uint8_t LongestBits(const Config &/*config*/) { return 31; }
class MiddlePointer {
public:
MiddlePointer(const DontQuantize & /*quant*/, unsigned char /*order_minus_2*/, util::BitAddress address) : address_(address) {}
MiddlePointer() : address_(NULL, 0) {}
bool Found() const {
return address_.base != NULL;
}
float Prob() const {
return util::ReadNonPositiveFloat31(address_.base, address_.offset);
}
float Backoff() const {
return util::ReadFloat32(address_.base, address_.offset + 31);
}
float Rest() const { return Prob(); }
void Write(float prob, float backoff) {
util::WriteNonPositiveFloat31(address_.base, address_.offset, prob);
util::WriteFloat32(address_.base, address_.offset + 31, backoff);
}
private:
util::BitAddress address_;
};
class LongestPointer {
public:
explicit LongestPointer(const DontQuantize &/*quant*/, util::BitAddress address) : address_(address) {}
LongestPointer() : address_(NULL, 0) {}
bool Found() const {
return address_.base != NULL;
}
float Prob() const {
return util::ReadNonPositiveFloat31(address_.base, address_.offset);
}
void Write(float prob) {
util::WriteNonPositiveFloat31(address_.base, address_.offset, prob);
}
private:
util::BitAddress address_;
};
DontQuantize() {}
void SetupMemory(void * /*start*/, unsigned char /*order*/, const Config & /*config*/) {}
static const bool kTrain = false;
// These should never be called because kTrain is false.
void Train(uint8_t /*order*/, std::vector<float> &/*prob*/, std::vector<float> &/*backoff*/) {}
void TrainProb(uint8_t, std::vector<float> &/*prob*/) {}
void FinishedLoading(const Config &) {}
};
class SeparatelyQuantize {
private:
class Bins {
public:
// Sigh C++ default constructor
Bins() {}
Bins(uint8_t bits, float *begin) : begin_(begin), end_(begin_ + (1ULL << bits)), bits_(bits), mask_((1ULL << bits) - 1) {}
float *Populate() { return begin_; }
uint64_t EncodeProb(float value) const {
return Encode(value, 0);
}
uint64_t EncodeBackoff(float value) const {
if (value == 0.0) {
return HasExtension(value) ? kExtensionQuant : kNoExtensionQuant;
}
return Encode(value, 2);
}
float Decode(std::size_t off) const { return begin_[off]; }
uint8_t Bits() const { return bits_; }
uint64_t Mask() const { return mask_; }
private:
uint64_t Encode(float value, size_t reserved) const {
const float *above = std::lower_bound(static_cast<const float*>(begin_) + reserved, end_, value);
if (above == begin_ + reserved) return reserved;
if (above == end_) return end_ - begin_ - 1;
return above - begin_ - (value - *(above - 1) < *above - value);
}
float *begin_;
const float *end_;
uint8_t bits_;
uint64_t mask_;
};
public:
static const ModelType kModelTypeAdd = kQuantAdd;
static void UpdateConfigFromBinary(int fd, const std::vector<uint64_t> &counts, Config &config);
static std::size_t Size(uint8_t order, const Config &config) {
size_t longest_table = (static_cast<size_t>(1) << static_cast<size_t>(config.prob_bits)) * sizeof(float);
size_t middle_table = (static_cast<size_t>(1) << static_cast<size_t>(config.backoff_bits)) * sizeof(float) + longest_table;
// unigrams are currently not quantized so no need for a table.
return (order - 2) * middle_table + longest_table + /* for the bit counts and alignment padding) */ 8;
}
static uint8_t MiddleBits(const Config &config) { return config.prob_bits + config.backoff_bits; }
static uint8_t LongestBits(const Config &config) { return config.prob_bits; }
class MiddlePointer {
public:
MiddlePointer(const SeparatelyQuantize &quant, unsigned char order_minus_2, const util::BitAddress &address) : bins_(quant.GetTables(order_minus_2)), address_(address) {}
MiddlePointer() : address_(NULL, 0) {}
bool Found() const { return address_.base != NULL; }
float Prob() const {
return ProbBins().Decode(util::ReadInt25(address_.base, address_.offset + BackoffBins().Bits(), ProbBins().Bits(), ProbBins().Mask()));
}
float Backoff() const {
return BackoffBins().Decode(util::ReadInt25(address_.base, address_.offset, BackoffBins().Bits(), BackoffBins().Mask()));
}
float Rest() const { return Prob(); }
void Write(float prob, float backoff) const {
util::WriteInt57(address_.base, address_.offset, ProbBins().Bits() + BackoffBins().Bits(),
(ProbBins().EncodeProb(prob) << BackoffBins().Bits()) | BackoffBins().EncodeBackoff(backoff));
}
private:
const Bins &ProbBins() const { return bins_[0]; }
const Bins &BackoffBins() const { return bins_[1]; }
const Bins *bins_;
util::BitAddress address_;
};
class LongestPointer {
public:
LongestPointer(const SeparatelyQuantize &quant, const util::BitAddress &address) : table_(&quant.LongestTable()), address_(address) {}
LongestPointer() : address_(NULL, 0) {}
bool Found() const { return address_.base != NULL; }
void Write(float prob) const {
util::WriteInt25(address_.base, address_.offset, table_->Bits(), table_->EncodeProb(prob));
}
float Prob() const {
return table_->Decode(util::ReadInt25(address_.base, address_.offset, table_->Bits(), table_->Mask()));
}
private:
const Bins *table_;
util::BitAddress address_;
};
SeparatelyQuantize() {}
void SetupMemory(void *start, unsigned char order, const Config &config);
static const bool kTrain = true;
// Assumes 0.0 is removed from backoff.
void Train(uint8_t order, std::vector<float> &prob, std::vector<float> &backoff);
// Train just probabilities (for longest order).
void TrainProb(uint8_t order, std::vector<float> &prob);
void FinishedLoading(const Config &config);
const Bins *GetTables(unsigned char order_minus_2) const { return tables_[order_minus_2]; }
const Bins &LongestTable() const { return longest_; }
private:
Bins tables_[KENLM_MAX_ORDER - 1][2];
Bins longest_;
uint8_t *actual_base_;
uint8_t prob_bits_, backoff_bits_;
};
} // namespace ngram
} // namespace lm
#endif // LM_QUANTIZE_H__
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