#!/bin/bash
  
  # Copyright   2013  Daniel Povey
  #             2014  David Snyder
  # Apache 2.0.
  
  # This script trains the i-vector extractor.  Note: there are 3 separate levels
  # of parallelization: num_threads, num_processes, and num_jobs.  This may seem a
  # bit excessive.  It has to do with minimizing memory usage and disk I/O,
  # subject to various constraints.  The "num_threads" is how many threads a
  # program uses; the "num_processes" is the number of separate processes a single
  # job spawns, and then sums the accumulators in memory.  Our recommendation:
  #  - Set num_threads to the minimum of (4, or how many virtual cores your machine has).
  #    (because of needing to lock various global quantities, the program can't
  #    use many more than 4 threads with good CPU utilization).
  #  - Set num_processes to the number of virtual cores on each machine you have, divided by
  #    num_threads.  E.g. 4, if you have 16 virtual cores.   If you're on a shared queue
  #    that's busy with other people's jobs, it may be wise to set it to rather less
  #    than this maximum though, or your jobs won't get scheduled.  And if memory is
  #    tight you need to be careful; in our normal setup, each process uses about 5G.
  #  - Set num_jobs to as many of the jobs (each using $num_threads * $num_processes CPUs)
  #    your queue will let you run at one time, but don't go much more than 10 or 20, or
  #    summing the accumulators will possibly get slow.  If you have a lot of data, you
  #    may want more jobs, though.
  
  # Begin configuration section.
  nj=10   # this is the number of separate queue jobs we run, but each one
          # contains num_processes sub-jobs.. the real number of threads we
          # run is nj * num_processes * num_threads, and the number of
          # separate pieces of data is nj * num_processes.
  num_threads=4
  num_processes=4 # each job runs this many processes, each with --num-threads threads
  cmd="run.pl"
  stage=-4
  num_gselect=20 # Gaussian-selection using diagonal model: number of Gaussians to select
  ivector_dim=600 # dimension of the extracted i-vector
  use_weights=false # set to true to turn on the regression of log-weights on the ivector.
  num_iters=10
  min_post=0.025 # Minimum posterior to use (posteriors below this are pruned out)
  num_samples_for_weights=3 # smaller than the default for speed (relates to a sampling method)
  cleanup=true
  posterior_scale=1.0 # This scale helps to control for successve features being highly
                      # correlated.  E.g. try 0.1 or 0.3
  sum_accs_opt=
  # 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 <fgmm-model> <data> <extractor-dir>"
    echo " e.g.: $0 exp/ubm_2048_male/final.ubm data/train_male exp/extractor_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 "  --num-iters <#iters|10>                          # Number of iterations of E-M"
    echo "  --nj <n|10>                                      # Number of jobs (also see num-processes and num-threads)"
    echo "  --num-processes <n|4>                            # Number of processes for each queue job (relates"
    echo "                                                   # to summing accs in memory)"
    echo "  --num-threads <n|4>                              # Number of threads for each process (can't be usefully"
    echo "                                                   # increased much above 4)"
    echo "  --stage <stage|-4>                               # To control partial reruns"
    echo "  --num-gselect <n|20>                             # Number of Gaussians to select using"
    echo "                                                   # diagonal model."
    echo "  --sum-accs-opt <option|''>                       # Option e.g. '-l hostname=a15' to localize"
    echo "                                                   # sum-accs process to nfs server."
    exit 1;
  fi
  
  fgmm_model=$1
  data=$2
  dir=$3
  
  for f in $fgmm_model $data/feats.scp ; do
    [ ! -f $f ] && echo "No such file $f" && exit 1;
  done
  
  # Set various variables.
  mkdir -p $dir/log
  nj_full=$[$nj*$num_processes]
  sdata=$data/split$nj_full;
  utils/split_data.sh $data $nj_full || exit 1;
  
  parallel_opts="--num-threads $[$num_threads*$num_processes]"
  ## 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:- |"
  
  # Initialize the i-vector extractor using the FGMM input
  if [ $stage -le -2 ]; then
    cp $fgmm_model $dir/final.ubm || exit 1;
    $cmd $dir/log/convert.log \
      fgmm-global-to-gmm $dir/final.ubm $dir/final.dubm || exit 1;
    $cmd $dir/log/init.log \
      ivector-extractor-init --ivector-dim=$ivector_dim --use-weights=$use_weights \
       $dir/final.ubm $dir/0.ie || exit 1
  fi
  
  # Do Gaussian selection and posterior extracion
  
  if [ $stage -le -1 ]; then
    echo $nj_full > $dir/num_jobs
    echo "$0: doing Gaussian selection and posterior computation"
    $cmd JOB=1:$nj_full $dir/log/gselect.JOB.log \
      gmm-gselect --n=$num_gselect $dir/final.dubm "$feats" ark:- \| \
      fgmm-global-gselect-to-post --min-post=$min_post $dir/final.ubm "$feats" \
        ark,s,cs:-  ark:- \| \
      scale-post ark:- $posterior_scale "ark:|gzip -c >$dir/post.JOB.gz" || exit 1;
  else
    if ! [ $nj_full -eq $(cat $dir/num_jobs) ]; then
      echo "Num-jobs mismatch $nj_full versus $(cat $dir/num_jobs)"
      exit 1
    fi
  fi
  
  x=0
  while [ $x -lt $num_iters ]; do
    if [ $stage -le $x ]; then
      rm $dir/.error 2>/dev/null
  
      Args=() # bash array of training commands for 1:nj, that put accs to stdout.
      for j in $(seq $nj_full); do
        Args[$j]=`echo "ivector-extractor-acc-stats --num-threads=$num_threads --num-samples-for-weights=$num_samples_for_weights $dir/$x.ie '$feats' 'ark,s,cs:gunzip -c $dir/post.JOB.gz|' -|" | sed s/JOB/$j/g`
      done
  
      echo "Accumulating stats (pass $x)"
      for g in $(seq $nj); do
        start=$[$num_processes*($g-1)+1]
        $cmd $parallel_opts $dir/log/acc.$x.$g.log \
          ivector-extractor-sum-accs --parallel=true "${Args[@]:$start:$num_processes}" \
            $dir/acc.$x.$g || touch $dir/.error &
      done
      wait
      [ -f $dir/.error ] && echo "Error accumulating stats on iteration $x" && exit 1;
      accs=""
      for j in $(seq $nj); do
        accs+="$dir/acc.$x.$j "
      done
      echo "Summing accs (pass $x)"
      $cmd $sum_accs_opt $dir/log/sum_acc.$x.log \
        ivector-extractor-sum-accs $accs $dir/acc.$x || exit 1;
      echo "Updating model (pass $x)"
      nt=$[$num_threads*$num_processes] # use the same number of threads that
                                        # each accumulation process uses, since we
                                        # can be sure the queue will support this many.
      $cmd --num-threads $nt $dir/log/update.$x.log \
        ivector-extractor-est --num-threads=$nt $dir/$x.ie $dir/acc.$x $dir/$[$x+1].ie || exit 1;
      rm $dir/acc.$x.*
      $cleanup && rm $dir/acc.$x $dir/$x.ie
    fi
    x=$[$x+1]
  done
  
  $cleanup && rm $dir/post.*.gz
  rm $dir/final.ie 2>/dev/null
  ln -s $x.ie $dir/final.ie