| 35 | 
  | 
 *                                                                       | 
| 36 | 
  | 
 * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).              | 
| 37 | 
  | 
 * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).           | 
| 38 | 
< | 
 * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).           | 
| 38 | 
> | 
 * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).           | 
| 39 | 
  | 
 * [4]  Kuang & Gezelter,  J. Chem. Phys. 133, 164101 (2010). | 
| 40 | 
  | 
 * [5]  Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011). | 
| 41 | 
  | 
 */ | 
| 44 | 
  | 
 * @file ForceField.cpp | 
| 45 | 
  | 
 * @author tlin | 
| 46 | 
  | 
 * @date 11/04/2004 | 
| 47 | 
– | 
 * @time 22:51am | 
| 47 | 
  | 
 * @version 1.0 | 
| 48 | 
  | 
 */ | 
| 49 | 
  | 
   | 
| 50 | 
  | 
#include <algorithm> | 
| 51 | 
< | 
#include "UseTheForce/ForceField.hpp" | 
| 51 | 
> | 
#include "brains/ForceField.hpp" | 
| 52 | 
  | 
#include "utils/simError.h" | 
| 53 | 
< | 
#include "utils/Tuple.hpp" | 
| 53 | 
> | 
 | 
| 54 | 
> | 
#include "io/OptionSectionParser.hpp" | 
| 55 | 
> | 
#include "io/BaseAtomTypesSectionParser.hpp" | 
| 56 | 
> | 
#include "io/DirectionalAtomTypesSectionParser.hpp" | 
| 57 | 
> | 
#include "io/AtomTypesSectionParser.hpp" | 
| 58 | 
> | 
#include "io/BendTypesSectionParser.hpp" | 
| 59 | 
> | 
#include "io/BondTypesSectionParser.hpp" | 
| 60 | 
> | 
#include "io/ChargeAtomTypesSectionParser.hpp" | 
| 61 | 
> | 
#include "io/EAMAtomTypesSectionParser.hpp" | 
| 62 | 
> | 
#include "io/FluctuatingChargeAtomTypesSectionParser.hpp" | 
| 63 | 
> | 
#include "io/GayBerneAtomTypesSectionParser.hpp" | 
| 64 | 
> | 
#include "io/InversionTypesSectionParser.hpp" | 
| 65 | 
> | 
#include "io/LennardJonesAtomTypesSectionParser.hpp" | 
| 66 | 
> | 
#include "io/MultipoleAtomTypesSectionParser.hpp" | 
| 67 | 
> | 
#include "io/NonBondedInteractionsSectionParser.hpp" | 
| 68 | 
> | 
#include "io/PolarizableAtomTypesSectionParser.hpp" | 
| 69 | 
> | 
#include "io/SCAtomTypesSectionParser.hpp" | 
| 70 | 
> | 
#include "io/ShapeAtomTypesSectionParser.hpp" | 
| 71 | 
> | 
#include "io/StickyAtomTypesSectionParser.hpp" | 
| 72 | 
> | 
#include "io/StickyPowerAtomTypesSectionParser.hpp" | 
| 73 | 
> | 
#include "io/TorsionTypesSectionParser.hpp" | 
| 74 | 
> | 
 | 
| 75 | 
> | 
#include "types/LennardJonesAdapter.hpp" | 
| 76 | 
> | 
#include "types/EAMAdapter.hpp" | 
| 77 | 
> | 
#include "types/SuttonChenAdapter.hpp" | 
| 78 | 
> | 
#include "types/GayBerneAdapter.hpp" | 
| 79 | 
> | 
#include "types/StickyAdapter.hpp" | 
| 80 | 
> | 
 | 
| 81 | 
  | 
namespace OpenMD { | 
| 82 | 
  | 
 | 
| 83 | 
< | 
  ForceField::ForceField() {  | 
| 83 | 
> | 
  ForceField::ForceField(std::string ffName) {  | 
| 84 | 
  | 
 | 
| 85 | 
  | 
    char* tempPath;  | 
| 86 | 
  | 
    tempPath = getenv("FORCE_PARAM_PATH"); | 
| 91 | 
  | 
    } else { | 
| 92 | 
  | 
      ffPath_ = tempPath; | 
| 93 | 
  | 
    } | 
| 94 | 
+ | 
 | 
| 95 | 
+ | 
    setForceFieldFileName(ffName + ".frc"); | 
| 96 | 
+ | 
 | 
| 97 | 
+ | 
    /** | 
| 98 | 
+ | 
     * The order of adding section parsers is important. | 
| 99 | 
+ | 
     * | 
| 100 | 
+ | 
     * OptionSectionParser must come first to set options for other | 
| 101 | 
+ | 
     * parsers | 
| 102 | 
+ | 
     *  | 
| 103 | 
+ | 
     * DirectionalAtomTypesSectionParser should be added before | 
| 104 | 
+ | 
     * AtomTypesSectionParser, and these two section parsers will | 
| 105 | 
+ | 
     * actually create "real" AtomTypes (AtomTypesSectionParser will | 
| 106 | 
+ | 
     * create AtomType and DirectionalAtomTypesSectionParser will | 
| 107 | 
+ | 
     * create DirectionalAtomType, which is a subclass of AtomType and | 
| 108 | 
+ | 
     * should come first).  | 
| 109 | 
+ | 
     * | 
| 110 | 
+ | 
     * Other AtomTypes Section Parsers will not create the "real" | 
| 111 | 
+ | 
     * AtomType, they only add and set some attributes of the AtomType | 
| 112 | 
+ | 
     * (via the Adapters). Thus ordering of these is not important. | 
| 113 | 
+ | 
     * AtomTypesSectionParser should be added before other atom type | 
| 114 | 
+ | 
     * | 
| 115 | 
+ | 
     * The order of BondTypesSectionParser, BendTypesSectionParser and | 
| 116 | 
+ | 
     * TorsionTypesSectionParser, etc. are not important. | 
| 117 | 
+ | 
     */ | 
| 118 | 
+ | 
 | 
| 119 | 
+ | 
    spMan_.push_back(new OptionSectionParser(forceFieldOptions_)); | 
| 120 | 
+ | 
    spMan_.push_back(new BaseAtomTypesSectionParser()); | 
| 121 | 
+ | 
    spMan_.push_back(new DirectionalAtomTypesSectionParser(forceFieldOptions_)); | 
| 122 | 
+ | 
    spMan_.push_back(new AtomTypesSectionParser()); | 
| 123 | 
+ | 
 | 
| 124 | 
+ | 
    spMan_.push_back(new LennardJonesAtomTypesSectionParser(forceFieldOptions_)); | 
| 125 | 
+ | 
    spMan_.push_back(new ChargeAtomTypesSectionParser(forceFieldOptions_)); | 
| 126 | 
+ | 
    spMan_.push_back(new MultipoleAtomTypesSectionParser(forceFieldOptions_)); | 
| 127 | 
+ | 
    spMan_.push_back(new FluctuatingChargeAtomTypesSectionParser(forceFieldOptions_)); | 
| 128 | 
+ | 
    spMan_.push_back(new PolarizableAtomTypesSectionParser(forceFieldOptions_)); | 
| 129 | 
+ | 
    spMan_.push_back(new GayBerneAtomTypesSectionParser(forceFieldOptions_)); | 
| 130 | 
+ | 
    spMan_.push_back(new EAMAtomTypesSectionParser(forceFieldOptions_)); | 
| 131 | 
+ | 
    spMan_.push_back(new SCAtomTypesSectionParser(forceFieldOptions_)); | 
| 132 | 
+ | 
    spMan_.push_back(new ShapeAtomTypesSectionParser(forceFieldOptions_)); | 
| 133 | 
+ | 
    spMan_.push_back(new StickyAtomTypesSectionParser(forceFieldOptions_)); | 
| 134 | 
+ | 
    spMan_.push_back(new StickyPowerAtomTypesSectionParser(forceFieldOptions_)); | 
| 135 | 
+ | 
 | 
| 136 | 
+ | 
    spMan_.push_back(new BondTypesSectionParser(forceFieldOptions_)); | 
| 137 | 
+ | 
    spMan_.push_back(new BendTypesSectionParser(forceFieldOptions_)); | 
| 138 | 
+ | 
    spMan_.push_back(new TorsionTypesSectionParser(forceFieldOptions_)); | 
| 139 | 
+ | 
    spMan_.push_back(new InversionTypesSectionParser(forceFieldOptions_)); | 
| 140 | 
+ | 
 | 
| 141 | 
+ | 
    spMan_.push_back(new NonBondedInteractionsSectionParser(forceFieldOptions_));     | 
| 142 | 
  | 
  } | 
| 143 | 
  | 
 | 
| 144 | 
+ | 
  void ForceField::parse(const std::string& filename) { | 
| 145 | 
+ | 
    ifstrstream* ffStream; | 
| 146 | 
+ | 
 | 
| 147 | 
+ | 
    ffStream = openForceFieldFile(filename); | 
| 148 | 
+ | 
 | 
| 149 | 
+ | 
    spMan_.parse(*ffStream, *this); | 
| 150 | 
+ | 
 | 
| 151 | 
+ | 
    ForceField::AtomTypeContainer::MapTypeIterator i; | 
| 152 | 
+ | 
    AtomType* at; | 
| 153 | 
+ | 
 | 
| 154 | 
+ | 
    for (at = atomTypeCont_.beginType(i); at != NULL;  | 
| 155 | 
+ | 
         at = atomTypeCont_.nextType(i)) { | 
| 156 | 
+ | 
 | 
| 157 | 
+ | 
      // useBase sets the responsibilities, and these have to be done  | 
| 158 | 
+ | 
      // after the atomTypes and Base types have all been scanned: | 
| 159 | 
+ | 
 | 
| 160 | 
+ | 
      std::vector<AtomType*> ayb = at->allYourBase();       | 
| 161 | 
+ | 
      if (ayb.size() > 1) { | 
| 162 | 
+ | 
        for (int j = ayb.size()-1; j > 0; j--) { | 
| 163 | 
+ | 
           | 
| 164 | 
+ | 
          ayb[j-1]->useBase(ayb[j]); | 
| 165 | 
+ | 
 | 
| 166 | 
+ | 
        } | 
| 167 | 
+ | 
      } | 
| 168 | 
+ | 
    } | 
| 169 | 
+ | 
 | 
| 170 | 
+ | 
    delete ffStream; | 
| 171 | 
+ | 
  } | 
| 172 | 
+ | 
 | 
| 173 | 
  | 
  /** | 
| 174 | 
  | 
   * getAtomType by string | 
| 175 | 
  | 
   * | 
| 227 | 
  | 
 | 
| 228 | 
  | 
      std::vector<std::pair<int, std::vector<std::string> > > foundBonds; | 
| 229 | 
  | 
 | 
| 230 | 
< | 
      for (i = at1Chain.begin(); i != at1Chain.end(); i++) { | 
| 230 | 
> | 
      for (i = at1Chain.begin(); i != at1Chain.end(); ++i) { | 
| 231 | 
  | 
        jj = 0; | 
| 232 | 
< | 
        for (j = at2Chain.begin(); j != at2Chain.end(); j++) { | 
| 232 | 
> | 
        for (j = at2Chain.begin(); j != at2Chain.end(); ++j) { | 
| 233 | 
  | 
 | 
| 234 | 
  | 
          bondTypeScore = ii + jj; | 
| 235 | 
  | 
 | 
| 247 | 
  | 
      } | 
| 248 | 
  | 
 | 
| 249 | 
  | 
 | 
| 250 | 
< | 
      if (foundBonds.size() > 0) { | 
| 250 | 
> | 
      if (!foundBonds.empty()) { | 
| 251 | 
  | 
        // sort the foundBonds by the score: | 
| 252 | 
  | 
        std::sort(foundBonds.begin(), foundBonds.end()); | 
| 253 | 
  | 
      | 
| 151 | 
– | 
        int bestScore = foundBonds[0].first; | 
| 254 | 
  | 
        std::vector<std::string> theKeys = foundBonds[0].second; | 
| 255 | 
  | 
         | 
| 256 | 
  | 
        BondType* bestType = bondTypeCont_.find(theKeys); | 
| 308 | 
  | 
 | 
| 309 | 
  | 
      std::vector<tuple3<int, int, std::vector<std::string> > > foundBends; | 
| 310 | 
  | 
 | 
| 311 | 
< | 
      for (j = at2Chain.begin(); j != at2Chain.end(); j++) { | 
| 311 | 
> | 
      for (j = at2Chain.begin(); j != at2Chain.end(); ++j) { | 
| 312 | 
  | 
        ii = 0; | 
| 313 | 
< | 
        for (i = at1Chain.begin(); i != at1Chain.end(); i++) { | 
| 313 | 
> | 
        for (i = at1Chain.begin(); i != at1Chain.end(); ++i) { | 
| 314 | 
  | 
          kk = 0; | 
| 315 | 
< | 
          for (k = at3Chain.begin(); k != at3Chain.end(); k++) { | 
| 315 | 
> | 
          for (k = at3Chain.begin(); k != at3Chain.end(); ++k) { | 
| 316 | 
  | 
           | 
| 317 | 
  | 
            IKscore = ii + kk; | 
| 318 | 
  | 
 | 
| 332 | 
  | 
        jj++; | 
| 333 | 
  | 
      } | 
| 334 | 
  | 
       | 
| 335 | 
< | 
      if (foundBends.size() > 0) { | 
| 335 | 
> | 
      if (!foundBends.empty()) { | 
| 336 | 
  | 
        std::sort(foundBends.begin(), foundBends.end()); | 
| 235 | 
– | 
        int jscore = foundBends[0].first; | 
| 236 | 
– | 
        int ikscore = foundBends[0].second; | 
| 337 | 
  | 
        std::vector<std::string> theKeys = foundBends[0].third;        | 
| 338 | 
  | 
         | 
| 339 | 
  | 
        BendType* bestType = bendTypeCont_.find(theKeys);   | 
| 402 | 
  | 
 | 
| 403 | 
  | 
      std::vector<tuple3<int, int, std::vector<std::string> > > foundTorsions; | 
| 404 | 
  | 
 | 
| 405 | 
< | 
      for (j = at2Chain.begin(); j != at2Chain.end(); j++) { | 
| 405 | 
> | 
      for (j = at2Chain.begin(); j != at2Chain.end(); ++j) { | 
| 406 | 
  | 
        kk = 0; | 
| 407 | 
< | 
        for (k = at3Chain.begin(); k != at3Chain.end(); k++) { | 
| 407 | 
> | 
        for (k = at3Chain.begin(); k != at3Chain.end(); ++k) { | 
| 408 | 
  | 
          ii = 0;        | 
| 409 | 
< | 
          for (i = at1Chain.begin(); i != at1Chain.end(); i++) { | 
| 409 | 
> | 
          for (i = at1Chain.begin(); i != at1Chain.end(); ++i) { | 
| 410 | 
  | 
            ll = 0; | 
| 411 | 
< | 
            for (l = at4Chain.begin(); l != at4Chain.end(); l++) { | 
| 411 | 
> | 
            for (l = at4Chain.begin(); l != at4Chain.end(); ++l) { | 
| 412 | 
  | 
           | 
| 413 | 
  | 
              ILscore = ii + ll; | 
| 414 | 
  | 
              JKscore = jj + kk; | 
| 432 | 
  | 
        jj++; | 
| 433 | 
  | 
      } | 
| 434 | 
  | 
       | 
| 435 | 
< | 
      if (foundTorsions.size() > 0) { | 
| 435 | 
> | 
      if (!foundTorsions.empty()) { | 
| 436 | 
  | 
        std::sort(foundTorsions.begin(), foundTorsions.end()); | 
| 337 | 
– | 
        int jkscore = foundTorsions[0].first; | 
| 338 | 
– | 
        int ilscore = foundTorsions[0].second; | 
| 437 | 
  | 
        std::vector<std::string> theKeys = foundTorsions[0].third; | 
| 438 | 
  | 
         | 
| 439 | 
  | 
        TorsionType* bestType = torsionTypeCont_.find(theKeys); | 
| 501 | 
  | 
       | 
| 502 | 
  | 
      std::vector<tuple3<int, int, std::vector<std::string> > > foundInversions; | 
| 503 | 
  | 
       | 
| 504 | 
< | 
      for (j = at2Chain.begin(); j != at2Chain.end(); j++) { | 
| 504 | 
> | 
      for (j = at2Chain.begin(); j != at2Chain.end(); ++j) { | 
| 505 | 
  | 
        kk = 0; | 
| 506 | 
< | 
        for (k = at3Chain.begin(); k != at3Chain.end(); k++) { | 
| 506 | 
> | 
        for (k = at3Chain.begin(); k != at3Chain.end(); ++k) { | 
| 507 | 
  | 
          ii = 0;        | 
| 508 | 
< | 
          for (i = at1Chain.begin(); i != at1Chain.end(); i++) { | 
| 508 | 
> | 
          for (i = at1Chain.begin(); i != at1Chain.end(); ++i) { | 
| 509 | 
  | 
            ll = 0; | 
| 510 | 
< | 
            for (l = at4Chain.begin(); l != at4Chain.end(); l++) { | 
| 510 | 
> | 
            for (l = at4Chain.begin(); l != at4Chain.end(); ++l) { | 
| 511 | 
  | 
               | 
| 512 | 
  | 
              Iscore = ii; | 
| 513 | 
  | 
              JKLscore = jj + kk + ll; | 
| 531 | 
  | 
        jj++; | 
| 532 | 
  | 
      } | 
| 533 | 
  | 
          | 
| 534 | 
< | 
      if (foundInversions.size() > 0) { | 
| 534 | 
> | 
      if (!foundInversions.empty()) { | 
| 535 | 
  | 
        std::sort(foundInversions.begin(), foundInversions.end()); | 
| 438 | 
– | 
        int iscore = foundInversions[0].first; | 
| 439 | 
– | 
        int jklscore = foundInversions[0].second; | 
| 536 | 
  | 
        std::vector<std::string> theKeys = foundInversions[0].third; | 
| 537 | 
  | 
         | 
| 538 | 
  | 
        InversionType* bestType = inversionTypeCont_.permutedFindSkippingFirstElement(theKeys); | 
| 578 | 
  | 
       | 
| 579 | 
  | 
      std::vector<std::pair<int, std::vector<std::string> > > foundNBI; | 
| 580 | 
  | 
       | 
| 581 | 
< | 
      for (i = at1Chain.begin(); i != at1Chain.end(); i++) { | 
| 581 | 
> | 
      for (i = at1Chain.begin(); i != at1Chain.end(); ++i) { | 
| 582 | 
  | 
        jj = 0; | 
| 583 | 
< | 
        for (j = at2Chain.begin(); j != at2Chain.end(); j++) { | 
| 583 | 
> | 
        for (j = at2Chain.begin(); j != at2Chain.end(); ++j) { | 
| 584 | 
  | 
           | 
| 585 | 
  | 
          nbiTypeScore = ii + jj; | 
| 586 | 
  | 
           | 
| 598 | 
  | 
      } | 
| 599 | 
  | 
       | 
| 600 | 
  | 
       | 
| 601 | 
< | 
      if (foundNBI.size() > 0) { | 
| 601 | 
> | 
      if (!foundNBI.empty()) { | 
| 602 | 
  | 
        // sort the foundNBI by the score: | 
| 603 | 
< | 
        std::sort(foundNBI.begin(), foundNBI.end()); | 
| 508 | 
< | 
         | 
| 509 | 
< | 
        int bestScore = foundNBI[0].first; | 
| 603 | 
> | 
        std::sort(foundNBI.begin(), foundNBI.end());        | 
| 604 | 
  | 
        std::vector<std::string> theKeys = foundNBI[0].second; | 
| 605 | 
  | 
         | 
| 606 | 
  | 
        NonBondedInteractionType* bestType = nonBondedInteractionTypeCont_.find(theKeys);         | 
| 729 | 
  | 
  } | 
| 730 | 
  | 
   | 
| 731 | 
  | 
  RealType ForceField::getRcutFromAtomType(AtomType* at) { | 
| 732 | 
< | 
    /**@todo */ | 
| 639 | 
< | 
    GenericData* data; | 
| 640 | 
< | 
    RealType rcut = 0.0; | 
| 732 | 
> | 
    RealType rcut(0.0); | 
| 733 | 
  | 
     | 
| 734 | 
< | 
    if (at->isLennardJones()) { | 
| 735 | 
< | 
      data = at->getPropertyByName("LennardJones"); | 
| 736 | 
< | 
      if (data != NULL) { | 
| 645 | 
< | 
        LJParamGenericData* ljData = dynamic_cast<LJParamGenericData*>(data); | 
| 646 | 
< | 
         | 
| 647 | 
< | 
        if (ljData != NULL) { | 
| 648 | 
< | 
          LJParam ljParam = ljData->getData(); | 
| 649 | 
< | 
           | 
| 650 | 
< | 
          //by default use 2.5*sigma as cutoff radius | 
| 651 | 
< | 
          rcut = 2.5 * ljParam.sigma; | 
| 652 | 
< | 
           | 
| 653 | 
< | 
        } else { | 
| 654 | 
< | 
          sprintf( painCave.errMsg, | 
| 655 | 
< | 
                   "Can not cast GenericData to LJParam\n"); | 
| 656 | 
< | 
          painCave.severity = OPENMD_ERROR; | 
| 657 | 
< | 
          painCave.isFatal = 1; | 
| 658 | 
< | 
          simError();           | 
| 659 | 
< | 
        }             | 
| 660 | 
< | 
      } else { | 
| 661 | 
< | 
        sprintf( painCave.errMsg, "Can not find Parameters for LennardJones\n"); | 
| 662 | 
< | 
        painCave.severity = OPENMD_ERROR; | 
| 663 | 
< | 
        painCave.isFatal = 1; | 
| 664 | 
< | 
        simError();           | 
| 665 | 
< | 
      } | 
| 734 | 
> | 
    LennardJonesAdapter lja = LennardJonesAdapter(at); | 
| 735 | 
> | 
    if (lja.isLennardJones()) { | 
| 736 | 
> | 
      rcut = 2.5 * lja.getSigma(); | 
| 737 | 
  | 
    } | 
| 738 | 
+ | 
    EAMAdapter ea = EAMAdapter(at); | 
| 739 | 
+ | 
    if (ea.isEAM()) { | 
| 740 | 
+ | 
      rcut = max(rcut, ea.getRcut()); | 
| 741 | 
+ | 
    } | 
| 742 | 
+ | 
    SuttonChenAdapter sca = SuttonChenAdapter(at); | 
| 743 | 
+ | 
    if (sca.isSuttonChen()) { | 
| 744 | 
+ | 
      rcut = max(rcut, 2.0 * sca.getAlpha()); | 
| 745 | 
+ | 
    } | 
| 746 | 
+ | 
    GayBerneAdapter gba = GayBerneAdapter(at); | 
| 747 | 
+ | 
    if (gba.isGayBerne()) { | 
| 748 | 
+ | 
      rcut = max(rcut, 2.5 * sqrt(2.0) * max(gba.getD(), gba.getL())); | 
| 749 | 
+ | 
    } | 
| 750 | 
+ | 
    StickyAdapter sa = StickyAdapter(at); | 
| 751 | 
+ | 
    if (sa.isSticky()) { | 
| 752 | 
+ | 
      rcut = max(rcut, max(sa.getRu(), sa.getRup())); | 
| 753 | 
+ | 
    } | 
| 754 | 
+ | 
 | 
| 755 | 
  | 
    return rcut;     | 
| 756 | 
  | 
  } | 
| 757 | 
  | 
   | 
| 761 | 
  | 
    ifstrstream* ffStream = new ifstrstream(); | 
| 762 | 
  | 
     | 
| 763 | 
  | 
    //try to open the force filed file in current directory first     | 
| 764 | 
< | 
    ffStream->open(forceFieldFilename.c_str()); | 
| 764 | 
> | 
    ffStream->open(forceFieldFilename.c_str(), ifstream::in | ifstream::binary); | 
| 765 | 
> | 
 | 
| 766 | 
  | 
    if(!ffStream->is_open()){ | 
| 767 | 
  | 
 | 
| 768 | 
  | 
      forceFieldFilename = ffPath_ + "/" + forceFieldFilename; | 
| 769 | 
< | 
      ffStream->open( forceFieldFilename.c_str() ); | 
| 769 | 
> | 
      ffStream->open( forceFieldFilename.c_str(),   | 
| 770 | 
> | 
                      ifstream::in | ifstream::binary ); | 
| 771 | 
  | 
 | 
| 772 | 
  | 
      //if current directory does not contain the force field file, | 
| 773 | 
  | 
      //try to open it in the path         |