#!/bin/bash
  # Copyright 2012  Johns Hopkins University (Author: Daniel Povey).  Apache 2.0.
  
  
  # Train a model on top of existing features (no feature-space learning of any
  # kind is done).  This script does not re-train the tree, it just does one iteration
  # of MAP adaptation to the model in the input alignment-directory.  It's useful for
  # adapting a system to a specific gender, or new acoustic conditions.
  
  # Note: what we implement here is not the MAP from the paper by Gauvain and Lee,
  # it's the simpler (and, I believe, more widely used) so-called "relevance MAP",
  # implemented in HTK, where we add a fixed count "tau" of fake Gaussian stats
  # generated from the old model, to the new 'in-domain' stats from the features
  # and alignments provided;  and we only update the mean.  So if the new count
  # is zero it just gives you the Gaussian parameters from the old model, but as
  # you get more than about tau counts, it approaches the in-domain stats.
  # We use 'gmm-ismooth-stats' in the command line because the equations for this
  # are the same as the equations for i-smoothing in discriminative training
  # (for which, see my [Dan Povey's] PhD thesis).
  
  # Begin configuration..
  cmd=run.pl
  stage=0
  tau=20 # smoothing constant used in MAP estimation, corresponds to the number of
         # "fake counts" that we add for the old model.  Larger tau corresponds to less
         # aggressive re-estimation, and more smoothing.  You might want to try 10 or 15 also
  # End configuration section.
  
  echo "$0 $@"  # Print the command line for logging
  
  [ -f path.sh ] && . ./path.sh
  . parse_options.sh || exit 1;
  
  if [ $# != 4 ]; then
    echo "Usage: steps/train_map.sh <data> <lang> <ali-dir> <exp-dir>"
    echo " e.g.: steps/train_map.sh data/train_si84_female data/lang exp/tri3c_ali_si84_female exp/tri4b_female"
    echo "Main options (for others, see top of script file)"
    echo "  --cmd (utils/run.pl|utils/queue.pl <queue opts>) # how to run jobs."
    echo "  --config <config-file>                           # config containing options"
    echo "  --stage <stage>                                  # stage to do partial re-run from."
    exit 1;
  fi
  
  data=$1
  lang=$2
  alidir=$3
  dir=$4
  
  for f in $data/feats.scp $lang/L.fst $alidir/ali.1.gz $alidir/final.mdl; do
    [ ! -f $f ] && echo "$0: no such file $f" && exit 1;
  done
  
  # Set various variables.
  nj=`cat $alidir/num_jobs` || exit 1;
  sdata=$data/split$nj
  splice_opts=`cat $alidir/splice_opts 2>/dev/null` # frame-splicing options.
  cmvn_opts=`cat $alidir/cmvn_opts 2>/dev/null`
  delta_opts=`cat $alidir/delta_opts 2>/dev/null`
  
  
  mkdir -p $dir/log
  
  utils/lang/check_phones_compatible.sh $lang/phones.txt $alidir/phones.txt || exit 1;
  cp $lang/phones.txt $dir || exit 1;
  
  cp $alidir/tree $dir
  # link ali.*.gz from $alidir to dest directory.
  utils/ln.pl $alidir/ali.*.gz $dir
  
  
  echo $nj >$dir/num_jobs
  cp $alidir/splice_opts $dir 2>/dev/null
  cp $alidir/cmvn_opts $dir 2>/dev/null # cmn/cmvn option.
  cp $alidir/delta_opts $dir 2>/dev/null
  [[ -d $sdata && $data/feats.scp -ot $sdata ]] || split_data.sh $data $nj || exit 1;
  
  ## Set up features.
  if [ -f $alidir/final.mat ]; then feat_type=lda; else feat_type=delta; fi
  echo "$0: feature type is $feat_type"
  
  case $feat_type in
    delta) sifeats="ark,s,cs:apply-cmvn $cmvn_opts --utt2spk=ark:$sdata/JOB/utt2spk scp:$sdata/JOB/cmvn.scp scp:$sdata/JOB/feats.scp ark:- | add-deltas $delta_opts ark:- ark:- |";;
    lda) sifeats="ark,s,cs:apply-cmvn $cmvn_opts --utt2spk=ark:$sdata/JOB/utt2spk scp:$sdata/JOB/cmvn.scp scp:$sdata/JOB/feats.scp ark:- | splice-feats $splice_opts ark:- ark:- | transform-feats $alidir/final.mat ark:- ark:- |"
      cp $alidir/final.mat $dir
      cp $alidir/full.mat $dir 2>/dev/null
      ;;
    *) echo "Invalid feature type $feat_type" && exit 1;
  esac
  if [ -f $alidir/trans.1 ]; then
    echo "$0: using transforms from $alidir"
    ln.pl $alidir/trans.* $dir # Link them to dest dir.
    feats="$sifeats transform-feats --utt2spk=ark:$sdata/JOB/utt2spk ark,s,cs:$dir/trans.JOB ark:- ark:- |"
  else
    feats="$sifeats"
  fi
  ##
  
  if [ $stage -le 0 ]; then
    $cmd JOB=1:$nj $dir/log/acc.JOB.log \
      gmm-acc-stats-ali  $alidir/final.mdl "$feats" \
      "ark,s,cs:gunzip -c $alidir/ali.JOB.gz|"  $dir/0.JOB.acc || exit 1;
  
    [ "`ls $dir/0.*.acc | wc -w`" -ne "$nj" ] && echo "$0: wrong #accs" && exit 1;
  
    $cmd $dir/log/sum_accs.log \
      gmm-sum-accs $dir/0.acc $dir/0.*.acc || exit 1;
  
    rm $dir/0.*.acc
  fi
  
  if [ $stage -le 1 ]; then
    # Update only the model means.  This is traditional in MAP estimation.
    $cmd $dir/log/update.log \
       gmm-ismooth-stats --smooth-from-model --tau=$tau $alidir/final.mdl $dir/0.acc - \| \
       gmm-est --update-flags=m --write-occs=$dir/final.occs --remove-low-count-gaussians=false \
             $alidir/final.mdl - $dir/final.mdl || exit 1;
  fi
  
  echo Done