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from libcpp.string cimport string
from libcpp.vector cimport vector
from cython.operator cimport dereference as deref
from utils cimport *
cimport hypergraph
cimport decoder
cimport lattice
cimport kbest as kb
SetSilent(True)
class ParseFailed(Exception):
pass
cdef class Weights:
cdef vector[weight_t]* weights
def __cinit__(self, Decoder decoder):
self.weights = &decoder.dec.CurrentWeightVector()
def __getitem__(self, char* fname):
cdef unsigned fid = FDConvert(fname)
if fid <= self.weights.size():
return self.weights[0][fid]
raise KeyError(fname)
def __setitem__(self, char* fname, float value):
cdef unsigned fid = FDConvert(<char *>fname)
if self.weights.size() <= fid:
self.weights.resize(fid + 1)
self.weights[0][fid] = value
def __iter__(self):
cdef unsigned fid
for fid in range(1, self.weights.size()):
yield FDConvert(fid).c_str(), self.weights[0][fid]
cdef class Decoder:
cdef decoder.Decoder* dec
cdef public Weights weights
def __cinit__(self, char* config):
decoder.register_feature_functions()
cdef istringstream* config_stream = new istringstream(config)
self.dec = new decoder.Decoder(config_stream)
del config_stream
self.weights = Weights(self)
def __dealloc__(self):
del self.dec
def read_weights(self, cfg):
with open(cfg) as fp:
for line in fp:
fname, value = line.split()
self.weights[fname.strip()] = float(value)
# TODO: list, lattice translation
def translate(self, unicode sentence, grammar=None):
if grammar:
self.dec.SetSentenceGrammarFromString(string(<char *> grammar))
inp = sentence.strip().encode('utf8')
cdef decoder.BasicObserver observer = decoder.BasicObserver()
self.dec.Decode(string(<char *>inp), &observer)
if observer.hypergraph == NULL:
raise ParseFailed()
cdef Hypergraph hg = Hypergraph()
hg.hg = new hypergraph.Hypergraph(observer.hypergraph[0])
return hg
cdef class Hypergraph:
cdef hypergraph.Hypergraph* hg
cdef MT19937* rng
def __dealloc__(self):
del self.hg
if self.rng != NULL:
del self.rng
def viterbi(self):
assert (self.hg != NULL)
cdef vector[WordID] trans
hypergraph.ViterbiESentence(self.hg[0], &trans)
cdef str sentence = GetString(trans).c_str()
return sentence.decode('utf8')
def viterbi_tree(self):
assert (self.hg != NULL)
cdef str tree = hypergraph.ViterbiETree(self.hg[0]).c_str()
return tree.decode('utf8')
def kbest(self, size):
assert (self.hg != NULL)
cdef kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal]* derivations = new kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal](self.hg[0], size)
cdef kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal].Derivation* derivation
cdef str tree
cdef unsigned k
for k in range(size):
derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
if not derivation: break
tree = GetString(derivation._yield).c_str()
yield tree.decode('utf8')
del derivations
def kbest_tree(self, size):
assert (self.hg != NULL)
cdef kb.KBestDerivations[vector[WordID], kb.ETreeTraversal]* derivations = new kb.KBestDerivations[vector[WordID], kb.ETreeTraversal](self.hg[0], size)
cdef kb.KBestDerivations[vector[WordID], kb.ETreeTraversal].Derivation* derivation
cdef str sentence
cdef unsigned k
for k in range(size):
derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
if not derivation: break
sentence = GetString(derivation._yield).c_str()
yield sentence.decode('utf8')
del derivations
def intersect(self, Lattice lat):
assert (self.hg != NULL)
hypergraph.Intersect(lat.lattice[0], self.hg)
def sample(self, unsigned n):
assert (self.hg != NULL)
cdef vector[hypergraph.Hypothesis]* hypos = new vector[hypergraph.Hypothesis]()
if self.rng == NULL:
self.rng = new MT19937()
hypergraph.sample_hypotheses(self.hg[0], n, self.rng, hypos)
cdef str sentence
cdef unsigned k
for k in range(hypos.size()):
sentence = GetString(hypos[0][k].words).c_str()
yield sentence.decode('utf8')
del hypos
# TODO: get feature expectations, get partition function ("inside" score)
# TODO: reweight the forest with different weights (Hypergraph::Reweight)
# TODO: inside-outside pruning
cdef class Lattice:
cdef lattice.Lattice* lattice
def __init__(self, tuple plf_tuple):
self.lattice = new lattice.Lattice()
cdef bytes plf = str(plf_tuple)
hypergraph.PLFtoLattice(string(<char *>plf), self.lattice)
def __str__(self):
return hypergraph.AsPLF(self.lattice[0]).c_str()
def __iter__(self):
return iter(eval(str(self)))
def __dealloc__(self):
del self.lattice
# TODO: wrap SparseVector
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