rdkit/Code/GraphMol/FragCatalog/FragCatalogUtils.cpp

//
//  Copyright (C) 2003-2006 Rational Discovery LLC
//
//   @@ All Rights Reserved @@
//  This file is part of the RDKit.
//  The contents are covered by the terms of the BSD license
//  which is included in the file license.txt, found at the root
//  of the RDKit source tree.
//

// REVIEW: move this to a GraphMol/FuncGroups directory

#include <RDGeneral/BadFileException.h>
#include "FragCatalogUtils.h"
#include <GraphMol/Subgraphs/Subgraphs.h>
#include <GraphMol/Subgraphs/SubgraphUtils.h>
#include <fstream>
#include <string>
#include <GraphMol/SmilesParse/SmilesParse.h>
#include <boost/tokenizer.hpp>
typedef boost::tokenizer<boost::char_separator<char>> tokenizer;
#include <boost/algorithm/string.hpp>

namespace RDKit {
// local utility namespace
namespace {
ROMol *getSmarts(std::string &&tmpStr) {
  ROMol *mol = nullptr;

  // Remove whitespace
  boost::trim(tmpStr);

  if (tmpStr.length() == 0) {
    // empty line
    return mol;
  }
  if (tmpStr.substr(0, 2) == "//") {
    // comment line
    return mol;
  }

  boost::char_separator<char> tabSep("\t");
  tokenizer tokens(tmpStr, tabSep);
  tokenizer::iterator token = tokens.begin();

  // name of the functional groups
  std::string name = *token;
  boost::erase_all(name, " ");
  ++token;

  // There must be a SMARTS expression
  CHECK_INVARIANT(token != tokens.end(), tmpStr);

  // grab the smarts:
  std::string smarts = *token;
  boost::erase_all(smarts, " ");
  ++token;

  mol = SmartsToMol(smarts);
  CHECK_INVARIANT(mol, smarts);
  mol->setProp(common_properties::_Name, name);
  mol->setProp(common_properties::_fragSMARTS, smarts);
  return mol;
}
}  // namespace

MOL_SPTR_VECT readFuncGroups(std::istream &inStream, int nToRead) {
  if (inStream.bad()) {
    throw BadFileException("Bad stream contents.");
  }

  int nRead = 0;

  MOL_SPTR_VECT funcGroups;
  while (!inStream.eof() && !inStream.fail() &&
         (nToRead < 0 || nRead < nToRead)) {
    std::string tmpstr;
    std::getline(inStream, tmpstr);
    // parse the molecule on this line (if there is one)
    ROMol *mol = getSmarts(std::move(tmpstr));
    if (mol) {
      funcGroups.push_back(ROMOL_SPTR(mol));
      nRead++;
    }
  }
  return funcGroups;
}

MOL_SPTR_VECT readFuncGroups(std::string fileName) {
  std::ifstream inStream(fileName.c_str());
  if ((!inStream) || (inStream.bad())) {
    std::ostringstream errout;
    errout << "Bad input file " << fileName;
    throw BadFileException(errout.str());
  }
  MOL_SPTR_VECT funcGroups;
  funcGroups = readFuncGroups(inStream);
  return funcGroups;
}

MatchVectType findFuncGroupsOnMol(const ROMol &mol, const FragCatParams *params,
                                  INT_VECT &fgBonds) {
  PRECONDITION(params, "bad params");

  fgBonds.clear();

  std::pair<int, int> amat;
  MatchVectType aidFgrps;
  std::vector<MatchVectType> fgpMatches;
  std::vector<MatchVectType>::const_iterator mati;
  MatchVectType::const_iterator mi;
  int aid;
  // const ROMol *fgrp;

  aidFgrps.clear();

  int fid = 0;
  const MOL_SPTR_VECT &fgrps = params->getFuncGroups();
  MOL_SPTR_VECT::const_iterator fgci;

  for (fgci = fgrps.begin(); fgci != fgrps.end(); fgci++) {
    const ROMol *fgrp = fgci->get();
    std::string fname;
    (*fgci)->getProp(common_properties::_Name, fname);
    // std::cout << "Groups number: " << fname << "\n";
    //(*fgci)->debugMol(std::cout);
    // mol->debugMol(std::cout);
    // match this functional group onto the molecule
    SubstructMatch(mol, *fgrp, fgpMatches);

    // loop over all the matches we get for this fgroup
    for (mati = fgpMatches.begin(); mati != fgpMatches.end(); mati++) {
      // FIX: we will assume that the first atom in fgrp is always the
      // connection
      // atom
      amat = mati->front();
      aid = amat.second;  // FIX: is this correct - the second entry in the pair
                          // is the atom ID from mol

      // grab the list of atom Ids from mol that match the functional group
      INT_VECT bondIds, maids;
      for (mi = mati->begin(); mi != mati->end(); mi++) {
        maids.push_back(mi->second);
      }

      // create a list of bond IDs from these atom ID
      // these are the bond in mol that are part of portion that matches the
      // functional group
      bondIds = Subgraphs::bondListFromAtomList(mol, maids);

      // now check if all these bonds have been covered as part of larger
      // functional group that was dealt with earlier
      // FIX: obviously we assume here that the function groups in params
      // come in decreasing order of size.
      bool allDone = true;
      for (auto bi : bondIds) {
        if (std::find(fgBonds.begin(), fgBonds.end(), bi) == fgBonds.end()) {
          allDone = false;
          fgBonds.push_back(bi);
        }
      }

      if (!allDone) {
        // this functional group mapping onto mol is not part of a larger func
        // group mapping so record it
        aidFgrps.push_back(std::pair<int, int>(aid, fid));
      }
    }
    fid++;
  }

  return aidFgrps;
}

ROMol *prepareMol(const ROMol &mol, const FragCatParams *fparams,
                  MatchVectType &aToFmap) {
  PRECONDITION(fparams, "");

  // get a mapping of the functional groups onto the molecule
  INT_VECT fgBonds;
  MatchVectType aidToFid = findFuncGroupsOnMol(mol, fparams, fgBonds);

  // get the core piece of molecule (i.e. the part of the molecule
  // without the functional groups). This basically the part of the molecule
  // that does not contain the function group bonds given by "fgBonds"
  INT_VECT cBonds;
  int bid, nbds = mol.getNumBonds();

  for (bid = 0; bid < nbds; bid++) {
    if (std::find(fgBonds.begin(), fgBonds.end(), bid) == fgBonds.end()) {
      cBonds.push_back(bid);
    }
  }

  INT_MAP_INT
  aIdxMap;  // a map from atom id in mol to the new atoms id in coreMol

  ROMol *coreMol = Subgraphs::pathToSubmol(mol, cBonds, false, aIdxMap);

  // now map the functional groups on mol to coreMol using aIdxMap
  MatchVectType::iterator mati;

  int newID;
  for (mati = aidToFid.begin(); mati != aidToFid.end(); mati++) {
    newID = aIdxMap[mati->first];
    aToFmap.push_back(std::pair<int, int>(newID, mati->second));
  }

  return coreMol;
}
}  // namespace RDKit