[src] Fixes to comments in chain-denominator.{h,cc} (kaldi-asr#3985)

Author: csukuangfj

src/chain/chain-den-graph.cc

@@ -132,7 +132,7 @@ void DenominatorGraph::SetInitialProbs(const fst::StdVectorFst &fst) {
     }
     cur_prob.Swap(&next_prob);
     next_prob.SetZero();
-    // Renormalize, beause the HMM won't sum to one even after the
+    // Renormalize, because the HMM won't sum to one even after the
     // previous normalization (due to final-probs).
     cur_prob.Scale(1.0 / cur_prob.Sum());
   }
@@ -181,7 +181,7 @@ void MapFstToPdfIdsPlusOne(const TransitionModel &trans_model,
 
 void MinimizeAcceptorNoPush(fst::StdVectorFst *fst) {
   BaseFloat delta = fst::kDelta * 10.0;  // use fairly loose delta for
-                                         // aggressive minimimization.
+                                         // aggressive minimization.
   fst::ArcMap(fst, fst::QuantizeMapper<fst::StdArc>(delta));
   fst::EncodeMapper<fst::StdArc> encoder(fst::kEncodeLabels | fst::kEncodeWeights,
                                          fst::ENCODE);
@@ -314,7 +314,7 @@ void CreateDenominatorFst(const ContextDependency &ctx_dep,
     AddSubsequentialLoop(subsequential_symbol, &phone_lm);
     fst::Project(&phone_lm, fst::PROJECT_INPUT);
   }
-  std::vector<int32> disambig_syms;  // empty list of diambiguation symbols.
+  std::vector<int32> disambig_syms;  // empty list of disambiguation symbols.
 
   // inv_cfst will be expanded on the fly, as needed.
   fst::InverseContextFst inv_cfst(subsequential_symbol,

src/chain/chain-den-graph.h

@@ -63,7 +63,7 @@ class DenominatorGraph {
   DenominatorGraph();
 
   // Initialize from epsilon-free acceptor FST with pdf-ids plus one as the
-  // labels.  'num_pdfs' is only needeed for checking.
+  // labels.  'num_pdfs' is only needed for checking.
   DenominatorGraph(const fst::StdVectorFst &fst,
                    int32 num_pdfs);
 
@@ -88,7 +88,7 @@ class DenominatorGraph {
   // Note: we renormalize each HMM-state to sum to one before doing this.
   const CuVector<BaseFloat> &InitialProbs() const;
 
-  // This function outputs a modifified version of the FST that was used to
+  // This function outputs a modified version of the FST that was used to
   // build this object, that has an initial-state with epsilon transitions to
   // each state, with weight determined by initial_probs_; and has each original
   // state being final with probability one (note: we remove epsilons).  This is
@@ -124,7 +124,7 @@ class DenominatorGraph {
   CuArray<Int32Pair> forward_transitions_;
   // backward_transitions_ is an array, indexed by hmm-state index,
   // of start and end indexes into the transition_ array, which
-  // give us the set of transitions out of this state.
+  // give us the set of transitions into this state.
   CuArray<Int32Pair> backward_transitions_;
   // This stores the actual transitions.
   CuArray<DenominatorGraphTransition> transitions_;
@@ -153,7 +153,7 @@ void MapFstToPdfIdsPlusOne(const TransitionModel &trans_model,
                            fst::StdVectorFst *fst);
 
 // Starting from an acceptor on phones that represents some kind of compiled
-// language model (with no disambiguation symbols), this funtion creates the
+// language model (with no disambiguation symbols), this function creates the
 // denominator-graph.  Note: there is similar code in chain-supervision.cc, when
 // creating the supervision graph.
 void CreateDenominatorFst(const ContextDependency &ctx_dep,

src/chain/chain-denominator.h

@@ -66,9 +66,9 @@ namespace chain {
 
   * Forward computation (version 1)
 
-  In the forward computation we're computing alpha(i, t) for 0 <= t <= T):
+  In the forward computation we're computing alpha(t, i) for 0 <= t <= T):
     - For the first frame, set alpha(0, i) = init(i), where init(i) is the
-      initial-probabilitiy from state i.  # in our framework these are obtained
+      initial-probability from state i.  # in our framework these are obtained
       #  by running the HMM for a while and getting an averaged occupation
       # probability, and using this as an initial-prob, since the boundaries of
       # chunks don't really correspond to utterance boundaries in general.]
@@ -161,7 +161,7 @@ namespace chain {
   - total-prob = \sum_i alpha'(T, i)
 
   The corrected log-prob that we return from the algorithm will be
-   (total-prob + \sum_{t=0}^{T-1} \log tot-alpha(t)).
+   (\log(total-prob) + \sum_{t=0}^{T-1} \log tot-alpha(t)).
 
   * Backward computation (version 3)