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Diffstat (limited to 'klm/lm/partial.hh')
| -rw-r--r-- | klm/lm/partial.hh | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/klm/lm/partial.hh b/klm/lm/partial.hh new file mode 100644 index 00000000..1dede359 --- /dev/null +++ b/klm/lm/partial.hh @@ -0,0 +1,167 @@ +#ifndef LM_PARTIAL__ +#define LM_PARTIAL__ + +#include "lm/return.hh" +#include "lm/state.hh" + +#include <algorithm> + +#include <assert.h> + +namespace lm { +namespace ngram { + +struct ExtendReturn { + float adjust; + bool make_full; + unsigned char next_use; +}; + +template <class Model> ExtendReturn ExtendLoop( + const Model &model, + unsigned char seen, const WordIndex *add_rbegin, const WordIndex *add_rend, const float *backoff_start, + const uint64_t *pointers, const uint64_t *pointers_end, + uint64_t *&pointers_write, + float *backoff_write) { + unsigned char add_length = add_rend - add_rbegin; + + float backoff_buf[2][KENLM_MAX_ORDER - 1]; + float *backoff_in = backoff_buf[0], *backoff_out = backoff_buf[1]; + std::copy(backoff_start, backoff_start + add_length, backoff_in); + + ExtendReturn value; + value.make_full = false; + value.adjust = 0.0; + value.next_use = add_length; + + unsigned char i = 0; + unsigned char length = pointers_end - pointers; + // pointers_write is NULL means that the existing left state is full, so we should use completed probabilities. + if (pointers_write) { + // Using full context, writing to new left state. + for (; i < length; ++i) { + FullScoreReturn ret(model.ExtendLeft( + add_rbegin, add_rbegin + value.next_use, + backoff_in, + pointers[i], i + seen + 1, + backoff_out, + value.next_use)); + std::swap(backoff_in, backoff_out); + if (ret.independent_left) { + value.adjust += ret.prob; + value.make_full = true; + ++i; + break; + } + value.adjust += ret.rest; + *pointers_write++ = ret.extend_left; + if (value.next_use != add_length) { + value.make_full = true; + ++i; + break; + } + } + } + // Using some of the new context. + for (; i < length && value.next_use; ++i) { + FullScoreReturn ret(model.ExtendLeft( + add_rbegin, add_rbegin + value.next_use, + backoff_in, + pointers[i], i + seen + 1, + backoff_out, + value.next_use)); + std::swap(backoff_in, backoff_out); + value.adjust += ret.prob; + } + float unrest = model.UnRest(pointers + i, pointers_end, i + seen + 1); + // Using none of the new context. + value.adjust += unrest; + + std::copy(backoff_in, backoff_in + value.next_use, backoff_write); + return value; +} + +template <class Model> float RevealBefore(const Model &model, const Right &reveal, const unsigned char seen, bool reveal_full, Left &left, Right &right) { + assert(seen < reveal.length || reveal_full); + uint64_t *pointers_write = reveal_full ? NULL : left.pointers; + float backoff_buffer[KENLM_MAX_ORDER - 1]; + ExtendReturn value(ExtendLoop( + model, + seen, reveal.words + seen, reveal.words + reveal.length, reveal.backoff + seen, + left.pointers, left.pointers + left.length, + pointers_write, + left.full ? backoff_buffer : (right.backoff + right.length))); + if (reveal_full) { + left.length = 0; + value.make_full = true; + } else { + left.length = pointers_write - left.pointers; + value.make_full |= (left.length == model.Order() - 1); + } + if (left.full) { + for (unsigned char i = 0; i < value.next_use; ++i) value.adjust += backoff_buffer[i]; + } else { + // If left wasn't full when it came in, put words into right state. + std::copy(reveal.words + seen, reveal.words + seen + value.next_use, right.words + right.length); + right.length += value.next_use; + left.full = value.make_full || (right.length == model.Order() - 1); + } + return value.adjust; +} + +template <class Model> float RevealAfter(const Model &model, Left &left, Right &right, const Left &reveal, unsigned char seen) { + assert(seen < reveal.length || reveal.full); + uint64_t *pointers_write = left.full ? NULL : (left.pointers + left.length); + ExtendReturn value(ExtendLoop( + model, + seen, right.words, right.words + right.length, right.backoff, + reveal.pointers + seen, reveal.pointers + reveal.length, + pointers_write, + right.backoff)); + if (reveal.full) { + for (unsigned char i = 0; i < value.next_use; ++i) value.adjust += right.backoff[i]; + right.length = 0; + value.make_full = true; + } else { + right.length = value.next_use; + value.make_full |= (right.length == model.Order() - 1); + } + if (!left.full) { + left.length = pointers_write - left.pointers; + left.full = value.make_full || (left.length == model.Order() - 1); + } + return value.adjust; +} + +template <class Model> float Subsume(const Model &model, Left &first_left, const Right &first_right, const Left &second_left, Right &second_right, const unsigned int between_length) { + assert(first_right.length < KENLM_MAX_ORDER); + assert(second_left.length < KENLM_MAX_ORDER); + assert(between_length < KENLM_MAX_ORDER - 1); + uint64_t *pointers_write = first_left.full ? NULL : (first_left.pointers + first_left.length); + float backoff_buffer[KENLM_MAX_ORDER - 1]; + ExtendReturn value(ExtendLoop( + model, + between_length, first_right.words, first_right.words + first_right.length, first_right.backoff, + second_left.pointers, second_left.pointers + second_left.length, + pointers_write, + second_left.full ? backoff_buffer : (second_right.backoff + second_right.length))); + if (second_left.full) { + for (unsigned char i = 0; i < value.next_use; ++i) value.adjust += backoff_buffer[i]; + } else { + std::copy(first_right.words, first_right.words + value.next_use, second_right.words + second_right.length); + second_right.length += value.next_use; + value.make_full |= (second_right.length == model.Order() - 1); + } + if (!first_left.full) { + first_left.length = pointers_write - first_left.pointers; + first_left.full = value.make_full || second_left.full || (first_left.length == model.Order() - 1); + } + assert(first_left.length < KENLM_MAX_ORDER); + assert(second_right.length < KENLM_MAX_ORDER); + return value.adjust; +} + +} // namespace ngram +} // namespace lm + +#endif // LM_PARTIAL__ |