// featbin/remove-mean.cc

// Copyright 2009-2011  Microsoft Corporation

// See ../../COPYING for clarification regarding multiple authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
// MERCHANTABLITY OR NON-INFRINGEMENT.
// See the Apache 2 License for the specific language governing permissions and
// limitations under the License.

#include "base/kaldi-common.h"
#include "util/common-utils.h"
#include "feat/feature-functions.h"
#include "matrix/kaldi-matrix.h"


int main(int argc, char *argv[]) {
  try {
    using namespace kaldi;

    const char *usage =
        "Remove mean from each feature file\n"
        " [ for per-speaker normalization, use add-cmvn-stats and apply-cmvn ]\n"
        "Usage: remove-mean [options] in-rspecifier out-wspecifier\n";

    ParseOptions po(usage);

    po.Read(argc, argv);

    if (po.NumArgs() != 2) {
      po.PrintUsage();
      exit(1);
    }

    std::string rspecifier = po.GetArg(1);
    std::string wspecifier = po.GetArg(2);

    BaseFloatMatrixWriter feat_writer(wspecifier);
    SequentialBaseFloatMatrixReader feat_reader(rspecifier);
    for (; !feat_reader.Done(); feat_reader.Next()) {
      std::string key = feat_reader.Key();
      Matrix<BaseFloat> feats (feat_reader.Value());
      if (feats.NumRows() == 0) {
        KALDI_WARN << "Empty feature matrix for key " << key;
        continue;
      }
      Vector<BaseFloat> mean(feats.NumCols());
      mean.AddRowSumMat(1.0, feats);
      mean.Scale(1.0 / feats.NumRows());
      for (int32 i = 0; i < feats.NumRows(); i++)
        feats.Row(i).AddVec(-1.0, mean);
      feat_writer.Write(key, feats);
    }
    return 0;
  } catch(const std::exception &e) {
    std::cerr << e.what();
    return -1;
  }
}