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
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
#ifndef LM_QUANTIZE_H__
#define LM_QUANTIZE_H__
#include "lm/blank.hh"
#include "lm/config.hh"
#include "lm/model_type.hh"
#include "util/bit_packing.hh"
#include <algorithm>
#include <vector>
#include <stdint.h>
#include <iostream>
namespace lm {
namespace ngram {
class 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; }
struct Middle {
void Write(void *base, uint64_t bit_offset, float prob, float backoff) const {
util::WriteNonPositiveFloat31(base, bit_offset, prob);
util::WriteFloat32(base, bit_offset + 31, backoff);
}
void Read(const void *base, uint64_t bit_offset, float &prob, float &backoff) const {
prob = util::ReadNonPositiveFloat31(base, bit_offset);
backoff = util::ReadFloat32(base, bit_offset + 31);
}
void ReadProb(const void *base, uint64_t bit_offset, float &prob) const {
prob = util::ReadNonPositiveFloat31(base, bit_offset);
}
void ReadBackoff(const void *base, uint64_t bit_offset, float &backoff) const {
backoff = util::ReadFloat32(base, bit_offset + 31);
}
uint8_t TotalBits() const { return 63; }
};
struct Longest {
void Write(void *base, uint64_t bit_offset, float prob) const {
util::WriteNonPositiveFloat31(base, bit_offset, prob);
}
void Read(const void *base, uint64_t bit_offset, float &prob) const {
prob = util::ReadNonPositiveFloat31(base, bit_offset);
}
uint8_t TotalBits() const { return 31; }
};
DontQuantize() {}
void SetupMemory(void * /*start*/, 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 &) {}
Middle Mid(uint8_t /*order*/) const { return Middle(); }
Longest Long(uint8_t /*order*/) const { return Longest(); }
};
class SeparatelyQuantize {
private:
class Bins {
public:
// Sigh C++ default constructor
Bins() {}
Bins(uint8_t bits, const float *const begin) : begin_(begin), end_(begin_ + (1ULL << bits)), bits_(bits), mask_((1ULL << bits) - 1) {}
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(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);
}
const 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 Middle {
public:
Middle(uint8_t prob_bits, const float *prob_begin, uint8_t backoff_bits, const float *backoff_begin) :
total_bits_(prob_bits + backoff_bits), total_mask_((1ULL << total_bits_) - 1), prob_(prob_bits, prob_begin), backoff_(backoff_bits, backoff_begin) {}
void Write(void *base, uint64_t bit_offset, float prob, float backoff) const {
util::WriteInt57(base, bit_offset, total_bits_,
(prob_.EncodeProb(prob) << backoff_.Bits()) | backoff_.EncodeBackoff(backoff));
}
void ReadProb(const void *base, uint64_t bit_offset, float &prob) const {
prob = prob_.Decode(util::ReadInt25(base, bit_offset + backoff_.Bits(), prob_.Bits(), prob_.Mask()));
}
void Read(const void *base, uint64_t bit_offset, float &prob, float &backoff) const {
uint64_t both = util::ReadInt57(base, bit_offset, total_bits_, total_mask_);
prob = prob_.Decode(both >> backoff_.Bits());
backoff = backoff_.Decode(both & backoff_.Mask());
}
void ReadBackoff(const void *base, uint64_t bit_offset, float &backoff) const {
backoff = backoff_.Decode(util::ReadInt25(base, bit_offset, backoff_.Bits(), backoff_.Mask()));
}
uint8_t TotalBits() const {
return total_bits_;
}
private:
const uint8_t total_bits_;
const uint64_t total_mask_;
const Bins prob_;
const Bins backoff_;
};
class Longest {
public:
// Sigh C++ default constructor
Longest() {}
Longest(uint8_t prob_bits, const float *prob_begin) : prob_(prob_bits, prob_begin) {}
void Write(void *base, uint64_t bit_offset, float prob) const {
util::WriteInt25(base, bit_offset, prob_.Bits(), prob_.EncodeProb(prob));
}
void Read(const void *base, uint64_t bit_offset, float &prob) const {
prob = prob_.Decode(util::ReadInt25(base, bit_offset, prob_.Bits(), prob_.Mask()));
}
uint8_t TotalBits() const { return prob_.Bits(); }
private:
Bins prob_;
};
SeparatelyQuantize() {}
void SetupMemory(void *start, 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);
Middle Mid(uint8_t order) const {
const float *table = start_ + TableStart(order);
return Middle(prob_bits_, table, backoff_bits_, table + ProbTableLength());
}
Longest Long(uint8_t order) const { return Longest(prob_bits_, start_ + TableStart(order)); }
private:
size_t TableStart(uint8_t order) const { return ((1ULL << prob_bits_) + (1ULL << backoff_bits_)) * static_cast<uint64_t>(order - 2); }
size_t ProbTableLength() const { return (1ULL << prob_bits_); }
float *start_;
uint8_t prob_bits_, backoff_bits_;
};
} // namespace ngram
} // namespace lm
#endif // LM_QUANTIZE_H__
|
