Move dictionary format independent probability calculation methods to ProbabilityUtils.

Bug: 6669677
Change-Id: Idc09a2fbb04e4d843e11313011178022177616aa
main
Keisuke Kuroyanagi 2013-06-01 14:08:20 -07:00
parent d3ccd4bf22
commit 88ad30f40b
5 changed files with 93 additions and 50 deletions

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@ -25,6 +25,7 @@
#include "suggest/core/dictionary/bloom_filter.h" #include "suggest/core/dictionary/bloom_filter.h"
#include "suggest/core/dictionary/char_utils.h" #include "suggest/core/dictionary/char_utils.h"
#include "suggest/core/dictionary/dictionary.h" #include "suggest/core/dictionary/dictionary.h"
#include "suggest/core/dictionary/probability_utils.h"
namespace latinime { namespace latinime {
@ -134,7 +135,7 @@ int BigramDictionary::getBigrams(const int *prevWord, int prevWordLength, int *i
// resulting probability is 8 - although in the practice it's never bigger than 3 or 4 // resulting probability is 8 - although in the practice it's never bigger than 3 or 4
// in very bad cases. This means that sometimes, we'll see some bigrams interverted // in very bad cases. This means that sometimes, we'll see some bigrams interverted
// here, but it can't get too bad. // here, but it can't get too bad.
const int probability = BinaryFormat::computeProbabilityForBigram( const int probability = ProbabilityUtils::computeProbabilityForBigram(
unigramProbability, bigramProbabilityTemp); unigramProbability, bigramProbabilityTemp);
addWordBigram(bigramBuffer, length, probability, bigramProbability, bigramCodePoints, addWordBigram(bigramBuffer, length, probability, bigramProbability, bigramCodePoints,
outputTypes); outputTypes);

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@ -23,6 +23,7 @@
#include "suggest/core/dictionary/binary_format.h" #include "suggest/core/dictionary/binary_format.h"
#include "suggest/core/dictionary/char_utils.h" #include "suggest/core/dictionary/char_utils.h"
#include "suggest/core/dictionary/multi_bigram_map.h" #include "suggest/core/dictionary/multi_bigram_map.h"
#include "suggest/core/dictionary/probability_utils.h"
#include "suggest/core/layout/proximity_info.h" #include "suggest/core/layout/proximity_info.h"
#include "suggest/core/layout/proximity_info_state.h" #include "suggest/core/layout/proximity_info_state.h"
@ -211,7 +212,7 @@ namespace latinime {
const int prevWordPos = node->getPrevWordPos(); const int prevWordPos = node->getPrevWordPos();
if (NOT_VALID_WORD == wordPos || NOT_VALID_WORD == prevWordPos) { if (NOT_VALID_WORD == wordPos || NOT_VALID_WORD == prevWordPos) {
// Note: Normally wordPos comes from the dictionary and should never equal NOT_VALID_WORD. // Note: Normally wordPos comes from the dictionary and should never equal NOT_VALID_WORD.
return backoff(unigramProbability); return ProbabilityUtils::backoff(unigramProbability);
} }
if (multiBigramMap) { if (multiBigramMap) {
return multiBigramMap->getBigramProbability( return multiBigramMap->getBigramProbability(

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@ -18,12 +18,12 @@
#define LATINIME_BINARY_FORMAT_H #define LATINIME_BINARY_FORMAT_H
#include <cstdlib> #include <cstdlib>
#include <map>
#include <stdint.h> #include <stdint.h>
#include "hash_map_compat.h" #include "hash_map_compat.h"
#include "suggest/core/dictionary/bloom_filter.h" #include "suggest/core/dictionary/bloom_filter.h"
#include "suggest/core/dictionary/char_utils.h" #include "suggest/core/dictionary/char_utils.h"
#include "suggest/core/dictionary/probability_utils.h"
namespace latinime { namespace latinime {
@ -91,10 +91,6 @@ class BinaryFormat {
const int length, const bool forceLowerCaseSearch); const int length, const bool forceLowerCaseSearch);
static int getWordAtAddress(const uint8_t *const root, const int address, const int maxDepth, static int getWordAtAddress(const uint8_t *const root, const int address, const int maxDepth,
int *outWord, int *outUnigramProbability); int *outWord, int *outUnigramProbability);
static int computeProbabilityForBigram(
const int unigramProbability, const int bigramProbability);
static int getProbability(const int position, const std::map<int, int> *bigramMap,
const uint8_t *bigramFilter, const int unigramProbability);
static int getBigramProbabilityFromHashMap(const int position, static int getBigramProbabilityFromHashMap(const int position,
const hash_map_compat<int, int> *bigramMap, const int unigramProbability); const hash_map_compat<int, int> *bigramMap, const int unigramProbability);
static float getMultiWordCostMultiplier(const uint8_t *const dict, const int dictSize); static float getMultiWordCostMultiplier(const uint8_t *const dict, const int dictSize);
@ -678,51 +674,18 @@ AK_FORCE_INLINE int BinaryFormat::getWordAtAddress(const uint8_t *const root, co
return 0; return 0;
} }
static inline int backoff(const int unigramProbability) {
return unigramProbability;
// For some reason, applying the backoff weight gives bad results in tests. To apply the
// backoff weight, we divide the probability by 2, which in our storing format means
// decreasing the score by 8.
// TODO: figure out what's wrong with this.
// return unigramProbability > 8 ? unigramProbability - 8 : (0 == unigramProbability ? 0 : 8);
}
inline int BinaryFormat::computeProbabilityForBigram(
const int unigramProbability, const int bigramProbability) {
// We divide the range [unigramProbability..255] in 16.5 steps - in other words, we want the
// unigram probability to be the median value of the 17th step from the top. A value of
// 0 for the bigram probability represents the middle of the 16th step from the top,
// while a value of 15 represents the middle of the top step.
// See makedict.BinaryDictInputOutput for details.
const float stepSize = static_cast<float>(MAX_PROBABILITY - unigramProbability)
/ (1.5f + MAX_BIGRAM_ENCODED_PROBABILITY);
return unigramProbability
+ static_cast<int>(static_cast<float>(bigramProbability + 1) * stepSize);
}
// This returns a probability in log space.
inline int BinaryFormat::getProbability(const int position, const std::map<int, int> *bigramMap,
const uint8_t *bigramFilter, const int unigramProbability) {
if (!bigramMap || !bigramFilter) return backoff(unigramProbability);
if (!isInFilter(bigramFilter, position)) return backoff(unigramProbability);
const std::map<int, int>::const_iterator bigramProbabilityIt = bigramMap->find(position);
if (bigramProbabilityIt != bigramMap->end()) {
const int bigramProbability = bigramProbabilityIt->second;
return computeProbabilityForBigram(unigramProbability, bigramProbability);
}
return backoff(unigramProbability);
}
// This returns a probability in log space. // This returns a probability in log space.
inline int BinaryFormat::getBigramProbabilityFromHashMap(const int position, inline int BinaryFormat::getBigramProbabilityFromHashMap(const int position,
const hash_map_compat<int, int> *bigramMap, const int unigramProbability) { const hash_map_compat<int, int> *bigramMap, const int unigramProbability) {
if (!bigramMap) return backoff(unigramProbability); if (!bigramMap) {
return ProbabilityUtils::backoff(unigramProbability);
}
const hash_map_compat<int, int>::const_iterator bigramProbabilityIt = bigramMap->find(position); const hash_map_compat<int, int>::const_iterator bigramProbabilityIt = bigramMap->find(position);
if (bigramProbabilityIt != bigramMap->end()) { if (bigramProbabilityIt != bigramMap->end()) {
const int bigramProbability = bigramProbabilityIt->second; const int bigramProbability = bigramProbabilityIt->second;
return computeProbabilityForBigram(unigramProbability, bigramProbability); return ProbabilityUtils::computeProbabilityForBigram(unigramProbability, bigramProbability);
} }
return backoff(unigramProbability); return ProbabilityUtils::backoff(unigramProbability);
} }
AK_FORCE_INLINE void BinaryFormat::fillBigramProbabilityToHashMap( AK_FORCE_INLINE void BinaryFormat::fillBigramProbabilityToHashMap(
@ -743,7 +706,9 @@ AK_FORCE_INLINE void BinaryFormat::fillBigramProbabilityToHashMap(
AK_FORCE_INLINE int BinaryFormat::getBigramProbability(const uint8_t *const root, int position, AK_FORCE_INLINE int BinaryFormat::getBigramProbability(const uint8_t *const root, int position,
const int nextPosition, const int unigramProbability) { const int nextPosition, const int unigramProbability) {
position = getBigramListPositionForWordPosition(root, position); position = getBigramListPositionForWordPosition(root, position);
if (0 == position) return backoff(unigramProbability); if (0 == position) {
return ProbabilityUtils::backoff(unigramProbability);
}
uint8_t bigramFlags; uint8_t bigramFlags;
do { do {
@ -752,10 +717,11 @@ AK_FORCE_INLINE int BinaryFormat::getBigramProbability(const uint8_t *const root
root, bigramFlags, &position); root, bigramFlags, &position);
if (bigramPos == nextPosition) { if (bigramPos == nextPosition) {
const int bigramProbability = MASK_ATTRIBUTE_PROBABILITY & bigramFlags; const int bigramProbability = MASK_ATTRIBUTE_PROBABILITY & bigramFlags;
return computeProbabilityForBigram(unigramProbability, bigramProbability); return ProbabilityUtils::computeProbabilityForBigram(
unigramProbability, bigramProbability);
} }
} while (FLAG_ATTRIBUTE_HAS_NEXT & bigramFlags); } while (FLAG_ATTRIBUTE_HAS_NEXT & bigramFlags);
return backoff(unigramProbability); return ProbabilityUtils::backoff(unigramProbability);
} }
// Returns a pointer to the start of the bigram list. // Returns a pointer to the start of the bigram list.

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@ -0,0 +1,74 @@
/*
* Copyright (C) 2013, The Android Open Source Project
*
* 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.
*/
#ifndef LATINIME_PROBABILITY_UTILS_H
#define LATINIME_PROBABILITY_UTILS_H
#include <map>
#include <stdint.h>
#include "defines.h"
namespace latinime {
class ProbabilityUtils {
public:
static AK_FORCE_INLINE int backoff(const int unigramProbability) {
return unigramProbability;
// For some reason, applying the backoff weight gives bad results in tests. To apply the
// backoff weight, we divide the probability by 2, which in our storing format means
// decreasing the score by 8.
// TODO: figure out what's wrong with this.
// return unigramProbability > 8 ?
// unigramProbability - 8 : (0 == unigramProbability ? 0 : 8);
}
static AK_FORCE_INLINE int computeProbabilityForBigram(
const int unigramProbability, const int bigramProbability) {
// We divide the range [unigramProbability..255] in 16.5 steps - in other words, we want
// the unigram probability to be the median value of the 17th step from the top. A value of
// 0 for the bigram probability represents the middle of the 16th step from the top,
// while a value of 15 represents the middle of the top step.
// See makedict.BinaryDictInputOutput for details.
const float stepSize = static_cast<float>(MAX_PROBABILITY - unigramProbability)
/ (1.5f + MAX_BIGRAM_ENCODED_PROBABILITY);
return unigramProbability
+ static_cast<int>(static_cast<float>(bigramProbability + 1) * stepSize);
}
// This returns a probability in log space.
static AK_FORCE_INLINE int getProbability(const int position,
const std::map<int, int> *const bigramMap,
const uint8_t *bigramFilter, const int unigramProbability) {
if (!bigramMap || !bigramFilter) {
return backoff(unigramProbability);
}
if (!isInFilter(bigramFilter, position)){
return backoff(unigramProbability);
}
const std::map<int, int>::const_iterator bigramProbabilityIt = bigramMap->find(position);
if (bigramProbabilityIt != bigramMap->end()) {
const int bigramProbability = bigramProbabilityIt->second;
return computeProbabilityForBigram(unigramProbability, bigramProbability);
}
return backoff(unigramProbability);
}
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ProbabilityUtils);
};
}
#endif /* LATINIME_PROBABILITY_UTILS_H */

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@ -23,6 +23,7 @@
#include "suggest/core/dictionary/char_utils.h" #include "suggest/core/dictionary/char_utils.h"
#include "suggest/core/dictionary/dictionary.h" #include "suggest/core/dictionary/dictionary.h"
#include "suggest/core/dictionary/digraph_utils.h" #include "suggest/core/dictionary/digraph_utils.h"
#include "suggest/core/dictionary/probability_utils.h"
#include "suggest/core/dictionary/terminal_attributes.h" #include "suggest/core/dictionary/terminal_attributes.h"
#include "suggest/core/layout/proximity_info.h" #include "suggest/core/layout/proximity_info.h"
#include "unigram_dictionary.h" #include "unigram_dictionary.h"
@ -935,8 +936,8 @@ bool UnigramDictionary::processCurrentNode(const int initialPos,
TerminalAttributes terminalAttributes(DICT_ROOT, flags, attributesPos); TerminalAttributes terminalAttributes(DICT_ROOT, flags, attributesPos);
// bigramMap contains the bigram frequencies indexed by addresses for fast lookup. // bigramMap contains the bigram frequencies indexed by addresses for fast lookup.
// bigramFilter is a bloom filter of said frequencies for even faster rejection. // bigramFilter is a bloom filter of said frequencies for even faster rejection.
const int probability = BinaryFormat::getProbability(initialPos, bigramMap, bigramFilter, const int probability = ProbabilityUtils::getProbability(
unigramProbability); initialPos, bigramMap, bigramFilter, unigramProbability);
onTerminal(probability, terminalAttributes, correction, queuePool, needsToInvokeOnTerminal, onTerminal(probability, terminalAttributes, correction, queuePool, needsToInvokeOnTerminal,
currentWordIndex); currentWordIndex);