subst_weight_matrix.hh

//------------------------------------------------------------------------------
// This file is part of the OpenStructure project <www.openstructure.org>
//
// Copyright (C) 2008-2020 by the OpenStructure authors
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the Free
// Software Foundation; either version 3.0 of the License, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
// details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this library; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//------------------------------------------------------------------------------
#ifndef OST_SEQ_SUBST_WEIGHT_MATRIX_HH
#define OST_SEQ_SUBST_WEIGHT_MATRIX_HH

#include <ctype.h>
#include <string.h>
#include <boost/shared_ptr.hpp>
#include <ost/config.hh>
#include <ost/seq/alg/module_config.hh>

/*
  Author: Marco Biasini
 */
namespace ost { namespace seq { namespace alg {

class SubstWeightMatrix;

typedef boost::shared_ptr<SubstWeightMatrix> SubstWeightMatrixPtr;
  
/// \brief position-independet substitution weight matrix  
class DLLEXPORT_OST_SEQ_ALG SubstWeightMatrix {
  
public:
  typedef short WeightType;
  const static int ALPHABET_SIZE='Z'-'A'+1;
  enum Preset{BLOSUM45 = 0,
              BLOSUM62 = 1,
              BLOSUM80 = 2,
              BLOSUM100 = 3};
  /// \brief Initialize substitution matrix with zero.
  /// 
  /// In order to get a useful  substitution weight matrix, use SetWeight(). 
  /// Alternatively you may want to load the substitution from an  info group.
  SubstWeightMatrix():max_weight_(0),min_weight_(0) {
    ::memset(weights_, 0, sizeof(WeightType)*ALPHABET_SIZE*ALPHABET_SIZE);
  }

  void AssignPreset(Preset p);

  /// \brief Get the substitution weight between two amino acids
  ///
  /// If the amino acid single letter code is unknown (e.g. '?')
  /// a weight of 0 is returned
  WeightType GetWeight(char aa_one, char aa_two) const 
  {
    if (!(IsAlpha(aa_one) && IsAlpha(aa_two))) {
      return 0;
    }
    int i=Index(aa_one, aa_two); 
    return (i>=0 && i<ALPHABET_SIZE*ALPHABET_SIZE) ? weights_[i] : 0;
  }

  /// \brief Get the minimal substitution weight of the matrix
  WeightType GetMinWeight() const { return min_weight_; }

  /// \brief Get the maximal substitution weight of the matrix
  WeightType GetMaxWeight() const { return max_weight_; }

  /// \brief Set the substitution weight between two amino acids
  ///
  /// The weight is only set if the amino acid single letter code
  /// is known (e.g. no weight is set for '?')
  void SetWeight(char aa_one, char aa_two, WeightType weight) 
  {
    if ((IsAlpha(aa_one) && IsAlpha(aa_two))) {
      int i=Index(aa_one, aa_two);
      if (i>=0 && i<ALPHABET_SIZE*ALPHABET_SIZE) {
        weights_[i]=weight;
        min_weight_ = std::min(min_weight_,weight);
        max_weight_ = std::max(max_weight_,weight);
      }
    }
  }

private:
  int Index(char aa_one, char aa_two) const {
    return (toupper(aa_one)-'A')*ALPHABET_SIZE+(toupper(aa_two)-'A');
  }

  /// \brief Check if uppercase character is one of [A-Z]
  bool IsAlpha(char aa) const {
    return (toupper(aa)>='A' && toupper(aa)<='Z');
  }
  WeightType weights_[ALPHABET_SIZE*ALPHABET_SIZE];
  WeightType max_weight_;
  WeightType min_weight_;
};

}}}

#endif