From 149232c38eec558ddb1097698d1570aacb67b59f Mon Sep 17 00:00:00 2001
From: Kenneth Heafield <github@kheafield.com>
Date: Wed, 16 May 2012 13:24:08 -0700
Subject: Big kenlm change includes lower order models for probing only.  And
 other stuff.

---
 klm/lm/value_build.cc | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 klm/lm/value_build.cc

(limited to 'klm/lm/value_build.cc')

diff --git a/klm/lm/value_build.cc b/klm/lm/value_build.cc
new file mode 100644
index 00000000..6124f8da
--- /dev/null
+++ b/klm/lm/value_build.cc
@@ -0,0 +1,58 @@
+#include "lm/value_build.hh"
+
+#include "lm/model.hh"
+#include "lm/read_arpa.hh"
+
+namespace lm { 
+namespace ngram {
+
+template <class Model> LowerRestBuild<Model>::LowerRestBuild(const Config &config, unsigned int order, const typename Model::Vocabulary &vocab) {
+  UTIL_THROW_IF(config.rest_lower_files.size() != order - 1, ConfigException, "This model has order " << order << " so there should be " << (order - 1) << " lower-order models for rest cost purposes.");
+  Config for_lower = config;
+  for_lower.rest_lower_files.clear();
+
+  // Unigram models aren't supported, so this is a custom loader.  
+  // TODO: optimize the unigram loading?  
+  {
+    util::FilePiece uni(config.rest_lower_files[0].c_str());
+    std::vector<uint64_t> number;
+    ReadARPACounts(uni, number);
+    UTIL_THROW_IF(number.size() != 1, FormatLoadException, "Expected the unigram model to have order 1, not " << number.size());
+    ReadNGramHeader(uni, 1);
+    unigrams_.resize(number[0]);
+    unigrams_[0] = config.unknown_missing_logprob;
+    PositiveProbWarn warn;
+    for (uint64_t i = 0; i < number[0]; ++i) {
+      WordIndex w;
+      Prob entry;
+      ReadNGram(uni, 1, vocab, &w, entry, warn);
+      unigrams_[w] = entry.prob;
+    }
+  }
+
+  try {
+    for (unsigned int i = 2; i < order; ++i) {
+      models_.push_back(new Model(config.rest_lower_files[i - 1].c_str(), for_lower));
+      UTIL_THROW_IF(models_.back()->Order() != i, FormatLoadException, "Lower order file " << config.rest_lower_files[i-1] << " should have order " << i);
+    }
+  } catch (...) {
+    for (typename std::vector<const Model*>::const_iterator i = models_.begin(); i != models_.end(); ++i) {
+      delete *i;
+    }
+    models_.clear();
+    throw;
+  }
+
+  // TODO: force/check same vocab.  
+}
+
+template <class Model> LowerRestBuild<Model>::~LowerRestBuild() {
+  for (typename std::vector<const Model*>::const_iterator i = models_.begin(); i != models_.end(); ++i) {
+    delete *i;
+  }
+}
+
+template class LowerRestBuild<ProbingModel>;
+
+} // namespace ngram
+} // namespace lm
-- 
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