rdkit/Code/GraphMol/Atom.cpp

// $Id$
//
//  Copyright (C) 2001-2006 Rational Discovery LLC
//
//   @@ All Rights Reserved  @@
//
#include <math.h>

#include "ROMol.h"
#include "Atom.h"
#include "PeriodicTable.h"
#include "SanitException.h"
#include <RDGeneral/Invariant.h>
#include <RDGeneral/RDLog.h>
#include <RDGeneral/types.h>

namespace RDKit {

Atom::Atom(){
  d_atomicNum=0;
  initAtom();
}

Atom::Atom(unsigned int num) {
  d_atomicNum = num;
  initAtom();
};

Atom::Atom(std::string what) {
  d_atomicNum = PeriodicTable::getTable()->getAtomicNumber(what);
  initAtom();
};

Atom::Atom( const Atom & other){
  // NOTE: we do *not* copy ownership!
  d_atomicNum = other.d_atomicNum;
  dp_mol = 0;
  d_index=0;
  d_formalCharge = other.d_formalCharge;
  df_noImplicit = other.df_noImplicit;
  df_isAromatic = other.df_isAromatic;
  d_dativeFlag = other.d_dativeFlag;
  d_numExplicitHs = other.d_numExplicitHs;
  d_mass = other.d_mass;
  d_pos = other.d_pos;
  d_chiralTag=other.d_chiralTag;
  d_hybrid = other.d_hybrid;
  d_implicitValence=other.d_implicitValence;
  d_explicitValence=other.d_explicitValence;
  if(other.dp_props){
    dp_props = new Dict(*other.dp_props);
  } else {
    dp_props = new Dict();
    STR_VECT computed;
    dp_props->setVal("computedProps", computed);
  }
}
void Atom::initAtom(){
  df_isAromatic = false;
  df_noImplicit = false;
  d_dativeFlag=0;
  d_numExplicitHs = 0;
  d_formalCharge = 0;
  d_index = 0;
  if(d_atomicNum){
    d_mass = PeriodicTable::getTable()->getAtomicWeight(d_atomicNum);
  } else{
    d_mass = 0.0;
  }
  d_chiralTag=CHI_UNSPECIFIED;
  d_hybrid = UNSPECIFIED;
  dp_mol = 0;
  dp_props = new Dict();

  d_implicitValence=-1;
  d_explicitValence=-1;

  // ok every Atom contains a property entry called "computedProps"
  // which provides list of property keys that correspond to value
  // that have been computed this can used to blow out all computed
  // properties while leaving the rest along initialize this list to
  // an empty vector of strings
  //STR_VECT computed;
  //dp_props->setVal("computedProps", computed);
}

Atom::~Atom()
{
  if(dp_props){
    delete dp_props;
    dp_props = 0;
  }
}

Atom *Atom::copy() const {
  Atom *res = new Atom(*this);
  return res;
}


void Atom::setOwningMol(ROMol *other)
{
  // NOTE: this operation does not update the topology of the owning
  // molecule (i.e. this atom is not added to the graph).  Only
  // molecules can add atoms to themselves.
  dp_mol = other;
}


std::string Atom::getSymbol() const {
  std::string res;
  // handle dummies differently:
  if(d_atomicNum != 0 || !hasProp("dummyLabel") ){
    res = PeriodicTable::getTable()->getElementSymbol(d_atomicNum);
  } else {
    getProp("dummyLabel",res);
  }
  return res;
}

unsigned int Atom::getDegree() const {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules")
  return getOwningMol().getAtomDegree(this);
}


//
//  If includeNeighbors is set, we'll loop over our neighbors
//   and include any of them that are Hs in the count here
//
unsigned int Atom::getTotalNumHs(bool includeNeighbors) const {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules")
  int res = getNumExplicitHs() + getNumImplicitHs();
  if(includeNeighbors){
    ROMol::ADJ_ITER begin,end;
    const ROMol *parent = &getOwningMol();
    boost::tie(begin,end) = parent->getAtomNeighbors(this);
    while(begin!=end){
      const Atom *at = parent->getAtomWithIdx(*begin);
      if(at->getAtomicNum()==1) res++;
      begin++;
    }
  }
  return res;
}

unsigned int Atom::getNumImplicitHs() const {
  PRECONDITION(d_implicitValence>-1,
	       "getNumImplicitHs() called without preceding call to calcImplicitValence()");
  return getImplicitValence();
}

int Atom::getExplicitValence(bool forceCalc) const {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules");
  PRECONDITION(d_explicitValence>-1,
	       "getExplicitValence() called without call to calcExplicitValence()");
  return d_explicitValence;
}
int Atom::calcExplicitValence(bool strict) {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules");
  unsigned int res;
  // FIX: contributions of bonds to valence are being done at best
  // approximately
  // EFF: this code is embarrassingly bad
  double accum=0;
  ROMol::OEDGE_ITER beg,end;
  boost::tie(beg,end) = getOwningMol().getAtomBonds(this);
  ROMol::GRAPH_MOL_BOND_PMAP::type pMap = getOwningMol().getBondPMap();
  while(beg!=end){
    accum += pMap[*beg]->getValenceContrib(this);
    beg++;
  }
  accum += getNumExplicitHs();

  // check accum is greater than the default valence
  unsigned int dv = PeriodicTable::getTable()->getDefaultValence(d_atomicNum);
  int chr = getFormalCharge();
  if (accum > (dv + chr)) {
    // check if this is because of aromaticity
    // set the accum back to the default valence
    if (this->getIsAromatic()) {
      // this needs some explanation if the atom is aromatic and
      // accum > (dv + chr) we assume that no hydrogen can be added
      // to this atom.  We set x = (v + chr) such that x is the
      // clossest possible integer to "accum" but less than
      // "accum". "v" here is one of the allowed valences e.g. if
      // sulfur in the following smiles : O=c1ccs(=O)cc1
      const UINT_VECT &valens = PeriodicTable::getTable()->getValenceList(d_atomicNum);
      UINT_VECT_CI vi;
      int val, pval = dv + chr;
      for (vi = valens.begin(); vi != valens.end(); vi++) {
	val = (*vi) + chr;
	if (val > accum) {
	  break;
	}
	else {
	  pval = val;
	}
      }
      accum = pval;
    }
  }
  // despite promising to not to blame it on him - this a trick Greg
  // came up with if we have a bond order sum of x.5 (i.e. 1.5, 2.5
  // etc) we would like it to round to the higher integer value so
  // 2.5 to 3 instead of 2, so we will add 0.1 to accum to assure
  // this plays a role in the number of hydrogen that are implicitly
  // added. This will only happen when the accum is a non-integer
  // value and less than the default valence (otherwise the above if
  // statement should have caught it). An example of where this can
  // happen is the following smiles:
  //    C1ccccC1
  // Daylight accepts this smiles and we should be able to Kekulize
  // correctly.
  accum += 0.1;

  res = static_cast<int>(round(accum));
  d_explicitValence = res;

  return res;
}

int Atom::getImplicitValence(bool forceCalc) const {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules");
  return d_implicitValence;
}

// NOTE: this uses the explicitValence, so you need to call calcExplicitValence()
// before calling this... updatePropertyCache() takes care of that.
int Atom::calcImplicitValence(bool strict) {
  PRECONDITION(dp_mol,"valence not defined for atoms not associated with molecules");
  if(d_explicitValence==-1) this->calcExplicitValence();
  // this is basically the difference between the allowed valence of
  // the atom and the explicit valence already specified - tells how
  // many Hs to add
  // 
  int res;
  // here is how we are going to deal with the possibility of
  // multiple valences
  // - check the explicit valence "ev"
  // - if it is already equal to one of the allowed valences for the
  //    atom return 0
  // - otherwise take return difference between next larger allowed
  //   valence and "ev"
  // if "ev" is greater than all allowed valences for the atom raise an exception
  // finally aromatic cases are dealt with differently - these atoms are allowed
  // only default valences
  const UINT_VECT &valens = PeriodicTable::getTable()->getValenceList(d_atomicNum);
  UINT_VECT_CI vi;
  int dv = PeriodicTable::getTable()->getDefaultValence(d_atomicNum);
  int explicitV = getExplicitValence();
  int chg = getFormalCharge();

  // NOTE: this is here to take care of the difference in element on
  // the right side of the carbon vs left side of carbon
  // For elements on the right side of the periodic table
  // (electronegative elements):
  //     NHYD = V - SBO + CHG
  // For elements on the left side of the periodic table
  // (electropositive elements):
  //      NHYD = V - SBO - CHG
  // This reflects that hydrogen adds to, for example, O as H+ while
  // it adds to Na as H-.

  // V = valence
  // SBO = Sum of bond orders
  // CHG = Formal charge

  //  It seems reasonable that the line is drawn at Carbon (in Group
  //  IV), but we must assume on which side of the line C
  //  falls... an assumption which will not always be correct.  For
  //  example:
  //  - Electropositive Carbon: a C with three singly-bonded
  //    neighbors (DV = 4, SBO = 3, CHG = 1) and a positive charge (a
  //    'stable' carbocation) should not have any hydrogens added.
  //  - Electronegative Carbon: C in isonitrile, R[N+]#[C-] (DV = 4, SBO = 3, 
  //    CHG = -1), also should not have any hydrogens added.
  //  Because isonitrile seems more relevant to pharma problems, we'll be
  //  making the second assumption:  *Carbon is electronegative*.
  //
  // So assuming you read all the above stuff - you know why we are
  // changing signs for "chg" here
  if ( (4 - PeriodicTable::getTable()->getNouterElecs(d_atomicNum)) > 0) {
    chg *= -1;
  }

  // if we have an aromatic case treat it differently
  if (getIsAromatic()) {
    if (explicitV <= (dv + chg)) {
      res = dv + chg - explicitV;
    }
    else {
      // As we assume when finding the explicitValence if we are
      // aromatic we should not be adding any hydrogen and already
      // be at an accepted valence state,

      // FIX: this is just ERROR checking and probably moot - the
      // explicitValence function called above should assure us that
      // we satisfy one of the accepted valence states for the
      // atom. The only diff I can think of is in the way we handle
      // formal charge here vs the explicit valence function.
      bool satis = false;
      for (vi = valens.begin(); vi != valens.end(); vi++) {
	if (explicitV == ((*vi) + chg)) {
	  satis = true;
	  break;
	}
      }
      if (strict && !satis) {
	std::ostringstream errout;
	errout << "Explicit valence for aromatic atom # " << getIdx() 
	       << " not equal to any accepted valence\n";
	std::string msg = errout.str();
	BOOST_LOG(rdErrorLog) << msg << std::endl;
	throw MolSanitizeException(msg);
      }
      res = 0;
    }
  }
  else {
    // non-aromatic case we are allowed to have non default valences
    // and be able to add hydrogens
    int tot;
    res = -1;
    for (vi = valens.begin(); vi != valens.end(); vi++) {
      tot = (*vi) + chg;
      if (explicitV <= tot) {
	res = tot - explicitV;
	break;
      }
    }
    if (res < 0) {
      if(strict){
	// this means that the explicit valen is greater than any
	// allowed valence for the atoms - raise an error
	std::ostringstream errout;
	errout << "Explicit valence for atom # " << getIdx() 
	       << " " << PeriodicTable::getTable()->getElementSymbol(d_atomicNum)
	       << " greater than permitted";
	std::string msg = errout.str();
	BOOST_LOG(rdErrorLog) << msg << std::endl;
	throw MolSanitizeException(msg);
      } else {
	res = 0;
      }
    }
  }
      
  d_implicitValence = res;
  return res;
}

void Atom::setQuery(Atom::QUERYATOM_QUERY *what) {
  //  Atoms don't have complex queries so this has to fail
  PRECONDITION(0,"plain atoms have no Query");
}
Atom::QUERYATOM_QUERY *Atom::getQuery() const {
  //PRECONDITION(0,"plain atoms have no Query");
  return NULL;
};
void Atom::expandQuery(Atom::QUERYATOM_QUERY *what,
		       Queries::CompositeQueryType how,
		       bool maintainOrder) {
  PRECONDITION(0,"plain atoms have no Query");
}

bool Atom::Match(Atom const *what) const {
  bool res = getAtomicNum() == what->getAtomicNum();
  return res;
}
bool Atom::Match(const Atom::ATOM_SPTR what) const {
  return Match(what.get());
}

void Atom::updatePropertyCache(bool strict) {
  calcExplicitValence(strict);
  calcImplicitValence(strict);
}

// returns the number of swaps required to convert the ordering
// of the probe list to match the order of our incoming bonds:
//
//  e.g. if our incoming bond order is: [0,1,2,3]:
//   getPerturbationOrder([1,0,2,3]) = 1
//   getPerturbationOrder([1,2,3,0]) = 3
//   getPerturbationOrder([1,2,0,3]) = 2
int Atom::getPerturbationOrder(INT_LIST probe) const{
  INT_LIST ref;
  ROMol::OEDGE_ITER beg,end;
  boost::tie(beg,end) = getOwningMol().getAtomBonds(this);
  ROMol::GRAPH_MOL_BOND_PMAP::type pMap = getOwningMol().getBondPMap();
  while(beg!=end){
    ref.push_back(pMap[*beg]->getIdx());
    beg++;
  }
  PRECONDITION(ref.size()==probe.size(),"size mismatch");
  INT_LIST::const_iterator refIt=ref.begin();
  INT_LIST::iterator probeIt=probe.begin(),probeIt2;

  int nSwaps = 0;
  while(refIt!=ref.end()){
    if((*probeIt)!=(*refIt)){
      bool foundIt=false;
      probeIt2=probeIt;
      while((*probeIt2)!=(*refIt) && probeIt2!=probe.end()){
	probeIt2++;
      }
      if(probeIt2 != probe.end()){
	foundIt=true;
      }
      CHECK_INVARIANT(foundIt,"could not find probe element");

      int tmp=*probeIt2;
      *probeIt2=*probeIt;
      *probeIt=tmp;
      nSwaps++;
    }
    probeIt++;
    refIt++;
  }
  return nSwaps;
}
  
} // end o' namespace

std::ostream & operator<<(std::ostream& target, const RDKit::Atom &at){
  target << at.getIdx() << " " << at.getAtomicNum() << " " << at.getSymbol();
  target << " chg: " << at.getFormalCharge();
  target << "  deg: " << at.getDegree();
  target << " exp: ";
  try {
    int explicitValence = at.getExplicitValence();
    target << explicitValence;
  } catch (...){
    target << "N/A";
  }
  target << " imp: ";
  try {
    int implicitValence = at.getImplicitValence();
    target << implicitValence;
  } catch (...){
    target << "N/A";
  }
  target << " hyb: " << at.getHybridization();
  target << " arom?: " << at.getIsAromatic();
  target << " chi: " << at.getChiralTag();
  return target;
};