#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__