#!/bin/bash
  # Copyright 2012  Johns Hopkins University (Author: Daniel Povey).  Apache 2.0.
  
  # MMI training (or optionally boosted MMI, if you give the --boost option).
  # 4 iterations (by default) of Extended Baum-Welch update.
  #
  # For the numerator we have a fixed alignment rather than a lattice--
  # this actually follows from the way lattices are defined in Kaldi, which
  # is to have a single path for each word (output-symbol) sequence.
  
  # Begin configuration section.
  cmd=run.pl
  num_iters=4
  boost=0.0
  cancel=true # if true, cancel num and den counts on each frame.
  drop_frames=false # if true, ignore stats from frames where num + den
                         # have no overlap. 
  tau=400
  weight_tau=10
  acwt=0.1
  stage=0
  # End configuration section
  
  echo "$0 $@"  # Print the command line for logging
  
  [ -f ./path.sh ] && . ./path.sh; # source the path.
  . parse_options.sh || exit 1;
  
  if [ $# -ne 5 ]; then
    echo "Usage: steps/train_mmi.sh <data> <lang> <ali> <denlats> <exp>"
    echo " e.g.: steps/train_mmi.sh data/train_si84 data/lang exp/tri2b_ali_si84 exp/tri2b_denlats_si84 exp/tri2b_mmi"
    echo "Main options (for others, see top of script file)"
    echo "  --boost <boost-weight>                           # (e.g. 0.1), for boosted MMI.  (default 0)"
    echo "  --cancel (true|false)                            # cancel stats (true by default)"
    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."
    echo "  --tau                                            # tau for i-smooth to last iter (default 200)"
    
    exit 1;
  fi
  
  data=$1
  lang=$2
  alidir=$3
  denlatdir=$4
  dir=$5
  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;
  
  for f in $data/feats.scp $alidir/{tree,final.mdl,ali.1.gz} $denlatdir/lat.1.gz; do
    [ ! -f $f ] && echo "$0: no such file $f" && exit 1;
  done
  nj=`cat $alidir/num_jobs` || exit 1;
  [ "$nj" -ne "`cat $denlatdir/num_jobs`" ] && \
    echo "$alidir and $denlatdir have different num-jobs" && exit 1;
  
  sdata=$data/split$nj
  splice_opts=`cat $alidir/splice_opts 2>/dev/null`
  cmvn_opts=`cat $alidir/cmvn_opts 2>/dev/null`
  delta_opts=`cat $alidir/delta_opts 2>/dev/null`
  mkdir -p $dir/log
  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;
  echo $nj > $dir/num_jobs
  
  cp $alidir/tree $dir
  cp $alidir/final.mdl $dir/0.mdl
  
  silphonelist=`cat $lang/phones/silence.csl` || 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) feats="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) feats="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    
      ;;
    *) echo "Invalid feature type $feat_type" && exit 1;
  esac
  
  [ -f $alidir/trans.1 ] && echo Using transforms from $alidir && \
    feats="$feats transform-feats --utt2spk=ark:$sdata/JOB/utt2spk ark,s,cs:$alidir/trans.JOB ark:- ark:- |"
  
  lats="ark:gunzip -c $denlatdir/lat.JOB.gz|"
  if [[ "$boost" != "0.0" && "$boost" != 0 ]]; then
    lats="$lats lattice-boost-ali --b=$boost --silence-phones=$silphonelist $alidir/final.mdl ark:- 'ark,s,cs:gunzip -c $alidir/ali.JOB.gz|' ark:- |"
  fi
  
  
  x=0
  while [ $x -lt $num_iters ]; do
    echo "Iteration $x of MMI training"
    # Note: the num and den states are accumulated at the same time, so we
    # can cancel them per frame.
    if [ $stage -le $x ]; then
      $cmd JOB=1:$nj $dir/log/acc.$x.JOB.log \
        gmm-rescore-lattice $dir/$x.mdl "$lats" "$feats" ark:- \| \
        lattice-to-post --acoustic-scale=$acwt ark:- ark:- \| \
        sum-post --drop-frames=$drop_frames --merge=$cancel --scale1=-1 \
        ark:- "ark,s,cs:gunzip -c $alidir/ali.JOB.gz | ali-to-post ark:- ark:- |" ark:- \| \
        gmm-acc-stats2 $dir/$x.mdl "$feats" ark,s,cs:- \
        $dir/num_acc.$x.JOB.acc $dir/den_acc.$x.JOB.acc || exit 1;
  
      n=`echo $dir/{num,den}_acc.$x.*.acc | wc -w`;
      [ "$n" -ne $[$nj*2] ] && \
        echo "Wrong number of MMI accumulators $n versus 2*$nj" && exit 1;
      $cmd $dir/log/den_acc_sum.$x.log \
        gmm-sum-accs $dir/den_acc.$x.acc $dir/den_acc.$x.*.acc || exit 1;
      rm $dir/den_acc.$x.*.acc
      $cmd $dir/log/num_acc_sum.$x.log \
        gmm-sum-accs $dir/num_acc.$x.acc $dir/num_acc.$x.*.acc || exit 1;
      rm $dir/num_acc.$x.*.acc
  
    # note: this tau value is for smoothing towards model parameters, not
    # as in the Boosted MMI paper, not towards the ML stats as in the earlier
    # work on discriminative training (e.g. my thesis).  
    # You could use gmm-ismooth-stats to smooth to the ML stats, if you had
    # them available [here they're not available if cancel=true].
  
      $cmd $dir/log/update.$x.log \
        gmm-est-gaussians-ebw --tau=$tau $dir/$x.mdl $dir/num_acc.$x.acc $dir/den_acc.$x.acc - \| \
        gmm-est-weights-ebw --weight-tau=$weight_tau - $dir/num_acc.$x.acc $dir/den_acc.$x.acc $dir/$[$x+1].mdl || exit 1;
      rm $dir/{den,num}_acc.$x.acc
    fi
  
    # Some diagnostics: the objective function progress and auxiliary-function
    # improvement.
  
    tail -n 50 $dir/log/acc.$x.*.log | perl -e '$acwt=shift @ARGV; while(<STDIN>) { if(m/gmm-acc-stats2.+Overall weighted acoustic likelihood per frame was (\S+) over (\S+) frames/) { $tot_aclike += $1*$2; $tot_frames1 += $2; } if(m|lattice-to-post.+Overall average log-like/frame is (\S+) over (\S+) frames.  Average acoustic like/frame is (\S+)|) { $tot_den_lat_like += $1*$2; $tot_frames2 += $2; $tot_den_aclike += $3*$2; } } if (abs($tot_frames1 - $tot_frames2) > 0.01*($tot_frames1 + $tot_frames2)) { print STDERR "Frame-counts disagree $tot_frames1 versus $tot_frames2
  "; } $tot_den_lat_like /= $tot_frames2; $tot_den_aclike /= $tot_frames2; $tot_aclike *= ($acwt / $tot_frames1);  $num_like = $tot_aclike + $tot_den_aclike; $per_frame_objf = $num_like - $tot_den_lat_like; print "$per_frame_objf $tot_frames1
  "; ' $acwt > $dir/tmpf
    objf=`cat $dir/tmpf | awk '{print $1}'`;
    nf=`cat $dir/tmpf | awk '{print $2}'`;
    rm $dir/tmpf
    impr=`grep -w Overall $dir/log/update.$x.log | awk '{x += $10*$12;} END{print x;}'`
    impr=`perl -e "print ($impr*$acwt/$nf);"` # We multiply by acwt, and divide by $nf which is the "real" number of frames.
    echo "Iteration $x: objf was $objf, MMI auxf change was $impr" | tee $dir/objf.$x.log
    x=$[$x+1]
  done
  
  echo "MMI training finished"
  
  rm $dir/final.mdl 2>/dev/null
  ln -s $x.mdl $dir/final.mdl
  
  exit 0;