#!/bin/bash
  
  # Copyright     2013  Daniel Povey
  #               2016  Brno University of Technology (author: Karel Vesely)
  # Apache 2.0.
  
  
  # This script computes iVectors in the same format as extract_ivectors_online.sh,
  # except that they are actually not really computed online, they are first computed
  # per speaker and just duplicated many times.
  # This is mainly intended for use in decoding, where you want the best possible
  # quality of iVectors.
  #
  # This setup also makes it possible to use a previous decoding or alignment, to
  # down-weight silence in the stats (default is --silence-weight 0.0).
  #
  # This is for when you use the "online-decoding" setup in an offline task, and
  # you want the best possible results.
  
  
  # Begin configuration section.
  nj=30
  cmd="run.pl"
  stage=0
  num_gselect=5 # Gaussian-selection using diagonal model: number of Gaussians to select
  min_post=0.025 # Minimum posterior to use (posteriors below this are pruned out)
  
  posterior_scale=0.1 # Scale on the acoustic posteriors, intended to account for
                      # inter-frame correlations.  Making this small during iVector
                      # extraction is equivalent to scaling up the prior, and will
                      # will tend to produce smaller iVectors where data-counts are
                      # small.  It's not so important that this match the value
                      # used when training the iVector extractor, but more important
                      # that this match the value used when you do real online decoding
                      # with the neural nets trained with these iVectors.
  
  max_count=100       # Interpret this as a number of frames times posterior scale...
                      # this config ensures that once the count exceeds this (i.e.
                      # 1000 frames, or 10 seconds, by default), we start to scale
                      # down the stats, accentuating the prior term.   This seems quite
                      # important for some reason.
  
  silence_weight=0.0
  acwt=0.1  # used if input is a decode dir, to get best path from lattices.
  mdl=final  # change this if decode directory did not have ../final.mdl present.
  
  # End configuration section.
  
  echo "$0 $@"  # Print the command line for logging
  
  if [ -f path.sh ]; then . ./path.sh; fi
  . parse_options.sh || exit 1;
  
  
  if [ $# != 4 ] && [ $# != 5 ]; then
    echo "Usage: $0 [options] <data> <lang> <extractor-dir> [<alignment-dir>|<decode-dir>|<weights-archive>] <ivector-dir>"
    echo " e.g.: $0 data/test exp/nnet2_online/extractor exp/tri3/decode_test exp/nnet2_online/ivectors_test"
    echo "main options (for others, see top of script file)"
    echo "  --config <config-file>                           # config containing options"
    echo "  --cmd (utils/run.pl|utils/queue.pl <queue opts>) # how to run jobs."
    echo "  --nj <n|10>                                      # Number of jobs (also see num-processes and num-threads)"
    echo "                                                   # Ignored if <alignment-dir> or <decode-dir> supplied."
    echo "  --stage <stage|0>                                # To control partial reruns"
    echo "  --num-gselect <n|5>                              # Number of Gaussians to select using"
    echo "                                                   # diagonal model."
    echo "  --min-post <float;default=0.025>                 # Pruning threshold for posteriors"
    echo "  --ivector-period <int;default=10>                # How often to extract an iVector (frames)"
    echo "  --posterior-scale <float;default=0.1>            # Scale on posteriors in iVector extraction; "
    echo "                                                   # affects strength of prior term."
  
    exit 1;
  fi
  
  set -euxo pipefail
  
  if [ $# -eq 4 ]; then
    data=$1
    lang=$2
    srcdir=$3
    dir=$4
  else # 5 arguments
    data=$1
    lang=$2
    srcdir=$3
    ali_or_decode_dir=$4
    dir=$5
  fi
  
  for f in $data/feats.scp $srcdir/final.ie $srcdir/final.dubm $lang/phones.txt; do
    [ ! -f $f ] && echo "$0: No such file $f" && exit 1;
  done
  
  mkdir -p $dir/log
  silphonelist=$(cat $lang/phones/silence.csl) || exit 1;
  
  if [ ! -z "$ali_or_decode_dir" ]; then
  
    if [ -f $ali_or_decode_dir/ali.1.gz ]; then
      if [ ! -f $ali_or_decode_dir/${mdl}.mdl ]; then
        echo "$0: expected $ali_or_decode_dir/${mdl}.mdl to exist."
        exit 1;
      fi
      nj_orig=$(cat $ali_or_decode_dir/num_jobs) || exit 1;
  
      if [ $stage -le 0 ]; then
        rm $dir/weights.*.gz 2>/dev/null || true
  
        $cmd JOB=1:$nj_orig  $dir/log/ali_to_post.JOB.log \
          gunzip -c $ali_or_decode_dir/ali.JOB.gz \| \
          ali-to-post ark:- ark:- \| \
          weight-silence-post $silence_weight $silphonelist $ali_or_decode_dir/final.mdl ark:- ark:- \| \
          post-to-weights ark:- "ark:|gzip -c >$dir/weights.JOB.gz" || exit 1;
  
        # put all the weights in one archive.
        for j in $(seq $nj_orig); do gunzip -c $dir/weights.$j.gz; done | gzip -c >$dir/weights.gz || exit 1;
        rm $dir/weights.*.gz || exit 1;
      fi
  
    elif [ -f $ali_or_decode_dir/lat.1.gz ]; then
      nj_orig=$(cat $ali_or_decode_dir/num_jobs) || exit 1;
      if [ ! -f $ali_or_decode_dir/../${mdl}.mdl ]; then
        echo "$0: expected $ali_or_decode_dir/../${mdl}.mdl to exist."
        exit 1;
      fi
  
  
      if [ $stage -le 0 ]; then
        rm $dir/weights.*.gz 2>/dev/null || true
  
        $cmd JOB=1:$nj_orig  $dir/log/lat_to_post.JOB.log \
          lattice-best-path --acoustic-scale=$acwt "ark:gunzip -c $ali_or_decode_dir/lat.JOB.gz|" ark:/dev/null ark:- \| \
          ali-to-post ark:- ark:- \| \
          weight-silence-post $silence_weight $silphonelist $ali_or_decode_dir/../${mdl}.mdl ark:- ark:- \| \
          post-to-weights ark:- "ark:|gzip -c >$dir/weights.JOB.gz" || exit 1;
  
        # put all the weights in one archive.
        for j in $(seq $nj_orig); do gunzip -c $dir/weights.$j.gz; done | gzip -c >$dir/weights.gz || exit 1;
        rm $dir/weights.*.gz || exit 1;
      fi
  
    elif [ -f $ali_or_decode_dir ] && gunzip -c $ali_or_decode_dir >/dev/null; then
      cp $ali_or_decode_dir $dir/weights.gz || exit 1;
  
    else
      echo "$0: expected ali.1.gz or lat.1.gz to exist in $ali_or_decode_dir";
      exit 1;
    fi
  fi
  
  sdata=$data/split$nj;
  utils/split_data.sh $data $nj || exit 1;
  
  gmm_feats="ark,s,cs:copy-feats scp:$sdata/JOB/feats.scp ark:- |"
  feats="$gmm_feats"
  
  # (here originally was the sub-speaker hack),
  this_sdata=$sdata
  
  # Per-speaker i-vectors,
  if [ $stage -le 2 ]; then
    if [ ! -z "$ali_or_decode_dir" ]; then
      $cmd JOB=1:$nj $dir/log/extract_ivectors.JOB.log \
        gmm-global-get-post --n=$num_gselect --min-post=$min_post $srcdir/final.dubm "$gmm_feats" ark:- \| \
        weight-post ark:- "ark,s,cs:gunzip -c $dir/weights.gz|" ark:- \| \
        ivector-extract --acoustic-weight=$posterior_scale --compute-objf-change=true \
          --max-count=$max_count --spk2utt=ark:$this_sdata/JOB/spk2utt \
        $srcdir/final.ie "$feats" ark,s,cs:- ark:$dir/ivectors_spk.JOB.ark
    else
      $cmd JOB=1:$nj $dir/log/extract_ivectors.JOB.log \
        gmm-global-get-post --n=$num_gselect --min-post=$min_post $srcdir/final.dubm "$gmm_feats" ark:- \| \
        ivector-extract --acoustic-weight=$posterior_scale --compute-objf-change=true \
          --max-count=$max_count --spk2utt=ark:$this_sdata/JOB/spk2utt \
        $srcdir/final.ie "$feats" ark,s,cs:- ark:$dir/ivectors_spk.JOB.ark
    fi
  fi
  
  # Per-utterance i-vectors,
  if [ $stage -le 3 ]; then
    if [ ! -z "$ali_or_decode_dir" ]; then
      $cmd JOB=1:$nj $dir/log/extract_ivectors_utt.JOB.log \
        gmm-global-get-post --n=$num_gselect --min-post=$min_post $srcdir/final.dubm "$gmm_feats" ark:- \| \
        weight-post ark:- "ark,s,cs:gunzip -c $dir/weights.gz|" ark:- \| \
        ivector-extract --acoustic-weight=$posterior_scale --compute-objf-change=true --max-count=$max_count \
        $srcdir/final.ie "$feats" ark,s,cs:- ark:$dir/ivectors_utt.JOB.ark
    else
      $cmd JOB=1:$nj $dir/log/extract_ivectors_utt.JOB.log \
        gmm-global-get-post --n=$num_gselect --min-post=$min_post $srcdir/final.dubm "$gmm_feats" ark:- \| \
        ivector-extract --acoustic-weight=$posterior_scale --compute-objf-change=true --max-count=$max_count \
        $srcdir/final.ie "$feats" ark,s,cs:- ark:$dir/ivectors_utt.JOB.ark
    fi
  fi
  
  absdir=$(utils/make_absolute.sh $dir)
  if [ $stage -le 4 ]; then
    echo "$0: merging iVectors across jobs"
    copy-vector "ark:cat $dir/ivectors_spk.*.ark |" ark,scp:$absdir/ivectors_spk.ark,$dir/ivectors_spk.scp
    rm $dir/ivectors_spk.*.ark
    copy-vector "ark:cat $dir/ivectors_utt.*.ark |" ark,scp:$absdir/ivectors_utt.ark,$dir/ivectors_utt.scp
    rm $dir/ivectors_utt.*.ark
  fi
  
  # duplicate the `speaker' i-vector to all `utterances' of that speaker,
  if [ $stage -le 5 ]; then
    # filter utt2spk (remove speakers with no iVector),
    awk -v ivec_spk=$dir/ivectors_spk.scp \
      'BEGIN{ while(getline < ivec_spk) { spk_has_ivec[$1] = 1; }} { spk=$2; if(spk_has_ivec[spk]) { print $0 }}' \
      $data/utt2spk >$dir/utt2spk.filt
    # expand the list of i-vectors,
    utils/apply_map.pl -f 2 $dir/ivectors_spk.scp <$dir/utt2spk.filt >$dir/ivectors_spk-as-utt.scp
  fi
  
  echo "$0: done extracting iVectors (per-speaker, per-sentence) into '$dir'"