#!/bin/bash
  
  # Copyright     2013  Daniel Povey
  #               2014  David Snyder
  # Apache 2.0.
  
  # This script extracts iVectors for a set of utterances, given
  # features and a trained iVector extractor.
  
  # Begin configuration section.
  nj=30
  cmd="run.pl"
  stage=0
  num_gselect=20 # 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=1.0 # This scale helps to control for successve features being highly
                      # correlated.  E.g. try 0.1 or 0.3.
  num_threads=1 # Number of threads used by ivector-extract.  It is usually not
                # helpful to set this to > 1.  It is only useful if you have
                # fewer speakers than the number of jobs you want to run.
  # 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 [ $# != 3 ]; then
    echo "Usage: $0 <extractor-dir> <data> <ivector-dir>"
    echo " e.g.: $0 exp/extractor_2048_male data/train_male exp/ivectors_male"
    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-threads)"
    echo "  --num-threads <n|1>                              # Number of threads for each job"
    echo "  --stage <stage|0>                                # To control partial reruns"
    echo "  --num-gselect <n|20>                             # Number of Gaussians to select using"
    echo "                                                   # diagonal model."
    echo "  --min-post <min-post|0.025>                      # Pruning threshold for posteriors"
    exit 1;
  fi
  
  srcdir=$1
  data=$2
  dir=$3
  
  for f in $srcdir/final.ie $srcdir/final.ubm $data/feats.scp $data/utt2lang; do
    [ ! -f $f ] && echo "No such file $f" && exit 1;
  done
  
  # Set various variables.
  mkdir -p $dir/log
  sdata=$data/split$nj;
  utils/split_data.sh $data $nj || exit 1;
  
  
  ## Set up features.
  feats="ark,s,cs:apply-cmvn-sliding --norm-vars=false --center=true --cmn-window=300 scp:$sdata/JOB/feats.scp ark:- | add-deltas-sdc ark:- ark:- | select-voiced-frames ark:- scp,s,cs:$sdata/JOB/vad.scp ark:- |"
  
  if [ $stage -le 0 ]; then
    echo "$0: extracting iVectors"
    dubm="fgmm-global-to-gmm $srcdir/final.ubm -|"
  
    $cmd --num-threads $num_threads JOB=1:$nj $dir/log/extract_ivectors.JOB.log \
      gmm-gselect --n=$num_gselect "$dubm" "$feats" ark:- \| \
      fgmm-global-gselect-to-post --min-post=$min_post $srcdir/final.ubm "$feats" \
        ark,s,cs:- ark:- \| scale-post ark:- $posterior_scale ark:- \| \
      ivector-extract --verbose=2 --num-threads=$num_threads $srcdir/final.ie "$feats" \
        ark,s,cs:- ark,scp,t:$dir/ivector.JOB.ark,$dir/ivector.JOB.scp || exit 1;
  fi
  
  if [ $stage -le 1 ]; then
    echo "$0: combining iVectors across jobs"
    for j in $(seq $nj); do cat $dir/ivector.$j.scp; done >$dir/ivector.scp || exit 1;
  fi
  
  if [ $stage -le 2 ]; then
    # Be careful here: the language-level iVectors are now length-normalized,
    # even if they are otherwise the same as the utterance-level ones.
    echo "$0: computing mean of iVectors for each speaker and length-normalizing"
    $cmd $dir/log/speaker_mean.log \
      ivector-normalize-length scp:$dir/ivector.scp  ark:- \| \
      ivector-mean "ark:utils/spk2utt_to_utt2spk.pl $data/utt2lang|" ark:- ark:- ark,t:$dir/num_utts.ark \| \
      ivector-normalize-length ark:- ark,scp:$dir/lang_ivector.ark,$dir/lang_ivector.scp || exit 1;
  fi