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Diffstat (limited to 'decoder/cfg_binarize.h')
-rw-r--r-- | decoder/cfg_binarize.h | 90 |
1 files changed, 0 insertions, 90 deletions
diff --git a/decoder/cfg_binarize.h b/decoder/cfg_binarize.h deleted file mode 100644 index ae06f8bf..00000000 --- a/decoder/cfg_binarize.h +++ /dev/null @@ -1,90 +0,0 @@ -#ifndef CFG_BINARIZE_H -#define CFG_BINARIZE_H - -#include <iostream> - -/* - binarization: decimate rhs of original rules until their rhs have been reduced to length 2 (or 1 if bin_unary). also decimate rhs of newly binarized rules until length 2. newly created rules are all binary (never unary/nullary). - - bin_name_nts: nts[i].from will be initialized, including adding new names to TD - - bin_l2r: right-branching (a (b c)) means suffixes are shared. if requested, the only other option that matters is bin_unary - - otherwise, greedy binarization: the pairs that are most frequent in the rules are binarized, one at a time. this should be done efficiently: each pair has a count of and list of its left and right adjacent pair+count (or maybe a non-count collapsed list of adjacent instances). this can be efficiently updated when a pair is chosen for replacement by a new virtual NT. - */ - -struct CFGBinarize { - int bin_thresh; - bool bin_l2r; - int bin_unary; - bool bin_name_nts; - bool bin_topo; - bool bin_split; - int split_passes,split_share1_passes,split_free_passes; - template <class Opts> // template to support both printable_opts and boost nonprintable - void AddOptions(Opts *opts) { - opts->add_options() - ("cfg_binarize_threshold", defaulted_value(&bin_thresh),"(if >0) repeatedly binarize CFG rhs bigrams which appear at least this many times, most frequent first. resulting rules may be 1,2, or >2-ary. this happens before the other types of binarization.") -// ("cfg_binarize_unary_threshold", defaulted_value(&bin_unary),"if >0, a rule-completing production A->BC may be binarized as A->U U->BC if U->BC would be used at least this many times. this happens last.") - ("cfg_binarize_split", defaulted_value(&bin_split),"(DeNero et al) for each rule until binarized, pick a split point k of L->r[0..n) to make rules L->V1 V2, V1->r[0..k) V2->r[k..n), to minimize the number of new rules created") - ("cfg_split_full_passes", defaulted_value(&split_passes),"pass through the virtual rules only (up to) this many times (all real rules will have been split if not already binary)") - ("cfg_split_share1_passes", defaulted_value(&split_share1_passes),"after the full passes, for up to this many times split when at least 1 of the items has been seen before") - ("cfg_split_free_passes", defaulted_value(&split_free_passes),"only split off from virtual nts pre/post nts that already exist - could check for interior phrases but after a few splits everything should be tiny already.") - ("cfg_binarize_l2r", defaulted_value(&bin_l2r),"force left to right (a (b (c d))) binarization (ignore _at threshold)") - ("cfg_binarize_name_nts", defaulted_value(&bin_name_nts),"create named virtual NT tokens e.g. 'A12+the' when binarizing 'B->[A12] the cat'") - ("cfg_binarize_topo", defaulted_value(&bin_topo),"reorder nonterminals after binarization to maintain definition before use (topological order). otherwise the virtual NTs will all appear after the regular NTs") - ; - } - void Validate() { - if (bin_thresh>0&&!bin_l2r) { -// std::cerr<<"\nWARNING: greedy binarization not yet supported; using l2r (right branching) instead.\n"; -// bin_l2r=true; - } - if (false && bin_l2r && bin_split) { // actually, split may be slightly incomplete due to finite number of passes. - std::cerr<<"\nWARNING: l2r and split are both complete binarization and redundant. Using split.\n"; - bin_l2r=false; - } - - } - - bool Binarizing() const { - return bin_split || bin_l2r || bin_thresh>0; - } - void set_defaults() { - bin_split=false; - bin_topo=false; - bin_thresh=0; - bin_unary=0; - bin_name_nts=true; - bin_l2r=false; - split_passes=10;split_share1_passes=0;split_free_passes=10; - } - CFGBinarize() { set_defaults(); } - void print(std::ostream &o) const { - o<<'('; - if (!Binarizing()) - o << "Unbinarized"; - else { - if (bin_unary) - o << "unary-sharing "; - if (bin_thresh) - o<<"greedy bigram count>="<<bin_thresh<<" "; - if (bin_l2r) - o << "left->right"; - else - o << "DeNero greedy split"; - if (bin_name_nts) - o << " named-NTs"; - if (bin_topo) - o<<" preserve-topo-order"; - } - o<<')'; - } - friend inline std::ostream &operator<<(std::ostream &o,CFGBinarize const& me) { - me.print(o); return o; - } - -}; - - -#endif |