Python Topology.setUnitCellDimensions方法代码示例

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def __init__(self, file):
        """Load a prmtop file."""
        top = Topology()
        ## The Topology read from the prmtop file
        self.topology = top

        # Load the prmtop file

        prmtop = amber_file_parser.PrmtopLoader(file)
        self._prmtop = prmtop

        # Add atoms to the topology

        PDBFile._loadNameReplacementTables()
        lastResidue = None
        c = top.addChain()
        for index in range(prmtop.getNumAtoms()):
            resNumber = prmtop.getResidueNumber(index)
            if resNumber != lastResidue:
                lastResidue = resNumber
                resName = prmtop.getResidueLabel(iAtom=index).strip()
                if resName in PDBFile._residueNameReplacements:
                    resName = PDBFile._residueNameReplacements[resName]
                r = top.addResidue(resName, c)
                if resName in PDBFile._atomNameReplacements:
                    atomReplacements = PDBFile._atomNameReplacements[resName]
                else:
                    atomReplacements = {}
            atomName = prmtop.getAtomName(index).strip()
            if atomName in atomReplacements:
                atomName = atomReplacements[atomName]

            # Try to guess the element.

            upper = atomName.upper()
            if upper.startswith('CL'):
                element = elem.chlorine
            elif upper.startswith('NA'):
                element = elem.sodium
            elif upper.startswith('MG'):
                element = elem.magnesium
            else:
                try:
                    element = elem.get_by_symbol(atomName[0])
                except KeyError:
                    element = None
            top.addAtom(atomName, element, r)

        # Add bonds to the topology

        atoms = list(top.atoms())
        for bond in prmtop.getBondsWithH():
            top.addBond(atoms[bond[0]], atoms[bond[1]])
        for bond in prmtop.getBondsNoH():
            top.addBond(atoms[bond[0]], atoms[bond[1]])

        # Set the periodic box size.

        if prmtop.getIfBox():
            top.setUnitCellDimensions(tuple(x.value_in_unit(unit.nanometer) for x in prmtop.getBoxBetaAndDimensions()[1:4])*unit.nanometer)

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def _createTopology(self):
        """Build the topology of the system
        """
        top = Topology()
        positions = []
        velocities = []

        boxVectors = []
        for x, y, z in self._conn.execute('SELECT x, y, z FROM global_cell'):
            boxVectors.append(mm.Vec3(x, y, z))
        unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
        top.setUnitCellDimensions(unitCellDimensions*angstrom)

        atoms = {}
        lastChain = None
        lastResId = None
        c = top.addChain()
        q = """SELECT id, name, anum, resname, resid, chain, x, y, z, vx, vy, vz
        FROM particle ORDER BY id"""
        for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z, vx, vy, vz) in self._conn.execute(q):
            newChain = False
            if chain != lastChain:
                lastChain = chain
                c = top.addChain()
                newChain = True
            if resId != lastResId or newChain:
                lastResId = resId
                if resName in PDBFile._residueNameReplacements:
                    resName = PDBFile._residueNameReplacements[resName]
                r = top.addResidue(resName, c)
                if resName in PDBFile._atomNameReplacements:
                    atomReplacements = PDBFile._atomNameReplacements[resName]
                else:
                    atomReplacements = {}

            if atomNumber == 0 and atomName.startswith('Vrt'):
                elem = None
            else:
                elem = Element.getByAtomicNumber(atomNumber)
            
            if atomName in atomReplacements:
                atomName = atomReplacements[atomName]

            atoms[atomId] = top.addAtom(atomName, elem, r)
            positions.append(mm.Vec3(x, y, z))

            velocities.append(mm.Vec3(vx, vy, vz))
    
        for p0, p1 in self._conn.execute('SELECT p0, p1 FROM bond'):
            top.addBond(atoms[p0], atoms[p1])

        positions = positions*angstrom
        velocities = velocities*angstrom/femtosecond
        return top, positions, velocities

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def delete(self, toDelete):
        """Delete chains, residues, atoms, and bonds from the model.

        You can specify objects to delete at any granularity: atoms, residues, or chains.  Passing
        in an Atom object causes that Atom to be deleted.  Passing in a Residue object causes that
        Residue and all Atoms it contains to be deleted.  Passing in a Chain object causes that
        Chain and all Residues and Atoms it contains to be deleted.

        In all cases, when an Atom is deleted, any bonds it participates in are also deleted.
        You also can specify a bond (as a tuple of Atom objects) to delete just that bond without
        deleting the Atoms it connects.

        Parameters:
         - toDelete (list) a list of Atoms, Residues, Chains, and bonds (specified as tuples of Atoms) to delete
        """
        newTopology = Topology()
        newTopology.setUnitCellDimensions(deepcopy(self.topology.getUnitCellDimensions()))
        newAtoms = {}
        newPositions = []*nanometer
        deleteSet = set(toDelete)
        for chain in self.topology.chains():
            if chain not in deleteSet:
                needNewChain = True;
                for residue in chain.residues():
                    if residue not in deleteSet:
                        needNewResidue = True
                        for atom in residue.atoms():
                            if atom not in deleteSet:
                                if needNewChain:
                                    newChain = newTopology.addChain()
                                    needNewChain = False;
                                if needNewResidue:
                                    newResidue = newTopology.addResidue(residue.name, newChain)
                                    needNewResidue = False;
                                newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
                                newAtoms[atom] = newAtom
                                newPositions.append(deepcopy(self.positions[atom.index]))
        for bond in self.topology.bonds():
            if bond[0] in newAtoms and bond[1] in newAtoms:
                if bond not in deleteSet and (bond[1], bond[0]) not in deleteSet:
                    newTopology.addBond(newAtoms[bond[0]], newAtoms[bond[1]])
        self.topology = newTopology
        self.positions = newPositions

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def _createTopology(self):
        '''Build the topology of the system
        '''
        top = Topology()
        positions = []

        boxVectors = []
        for x, y, z in self._conn.execute('SELECT x, y, z FROM global_cell'):
            boxVectors.append(mm.Vec3(x, y, z)*angstrom)
        unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
        top.setUnitCellDimensions(unitCellDimensions)

        atoms = {}
        lastChain = None
        lastResId = None
        c = top.addChain()
        q = '''SELECT id, name, anum, resname, resid, chain, x, y, z
        FROM particle'''
        for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z) in self._conn.execute(q):
            if chain != lastChain:
                lastChain = chain
                c = top.addChain()
            if resId != lastResId:
                lastResId = resId
                if resName in PDBFile._residueNameReplacements:
                    resName = PDBFile._residueNameReplacements[resName]
                r = top.addResidue(resName, c)
                if resName in PDBFile._atomNameReplacements:
                    atomReplacements = PDBFile._atomNameReplacements[resName]
                else:
                    atomReplacements = {}

            if atomName in atomReplacements:
                atomName = atomReplacements[atomName]

            elem = Element.getByAtomicNumber(atomNumber)
            atoms[atomId] = top.addAtom(atomName, elem, r)
            positions.append(mm.Vec3(x, y, z)*angstrom)

        for p0, p1 in self._conn.execute('SELECT p0, p1 FROM bond'):
            top.addBond(atoms[p0], atoms[p1])

        return top, positions

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def add(self, addTopology, addPositions):
        """Add chains, residues, atoms, and bonds to the model.

        Specify what to add by providing a new Topology object and the corresponding atomic positions.
        All chains, residues, atoms, and bonds contained in the Topology are added to the model.

        Parameters:
         - addTopoology (Topology) a Topology whose contents should be added to the model
         - addPositions (list) the positions of the atoms to add
        """
        # Copy over the existing model.

        newTopology = Topology()
        newTopology.setUnitCellDimensions(deepcopy(self.topology.getUnitCellDimensions()))
        newAtoms = {}
        newPositions = []*nanometer
        for chain in self.topology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)
                for atom in residue.atoms():
                    newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
                    newAtoms[atom] = newAtom
                    newPositions.append(deepcopy(self.positions[atom.index]))
        for bond in self.topology.bonds():
            newTopology.addBond(newAtoms[bond[0]], newAtoms[bond[1]])

        # Add the new model

        newAtoms = {}
        for chain in addTopology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)
                for atom in residue.atoms():
                    newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
                    newAtoms[atom] = newAtom
                    newPositions.append(deepcopy(addPositions[atom.index]))
        for bond in addTopology.bonds():
            newTopology.addBond(newAtoms[bond[0]], newAtoms[bond[1]])
        self.topology = newTopology
        self.positions = newPositions

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]

#.........这里部分代码省略.........
        """
        # If anything changed, rebuild the topology
        if not self._topology_changed():
            try:
                return self._topology
            except AttributeError:
                pass
        else:
            self.remake_parm()
      
        self._topology = Topology()

        # Add all of the atoms to the topology file in the same chain
        chain = self._topology.addChain()
        last_residue = None
        for i, atm in enumerate(self.atom_list):
            resnum = atm.residue.idx
            if last_residue != resnum:
                last_residue = resnum
                resname = atm.residue.resname
                res = self._topology.addResidue(resname, chain)
            elem = element.get_by_symbol(pt.Element[atm.element])
            self._topology.addAtom(atm.atname, elem, res)

        # Add bonds to the topology (both with and without hydrogen)
        atoms = list(self._topology.atoms())
        for bnd in self.bonds_inc_h + self.bonds_without_h:
            self._topology.addBond(atoms[bnd.atom1.starting_index],
                                   atoms[bnd.atom2.starting_index])
      
        # Set the box dimensions
        if self.ptr('ifbox'):
            if hasattr(self, 'rst7'):
                self._topology.setUnitCellDimensions(
                        self.rst7.box[:3]*u.angstrom
                )
            else:
                self._topology.setUnitCellDimensions(
                        self.parm_data['BOX_DIMENSIONS'][1:4]*u.angstrom
                )

        return self._topology
   
    def _get_gb_params(self, gb_model=HCT):
        """ Gets the GB parameters. Need this method to special-case GB neck """
        if gb_model is GBn:
            screen = [0.5 for atom in self.atom_list]
            for i, atom in enumerate(self.atom_list):
                if atom.element == 6:
                    screen[i] = 0.48435382330
                elif atom.element == 1:
                    screen[i] = 1.09085413633
                elif atom.element == 7:
                    screen[i] = 0.700147318409
                elif atom.element == 8:
                    screen[i] = 1.06557401132
                elif atom.element == 16:
                    screen[i] = 0.602256336067
        elif gb_model is GBn2:
            # Add non-optimized values as defaults
            alpha = [1.0 for i in self.atom_list]
            beta = [0.8 for i in self.atom_list]
            gamma = [4.85 for i in self.atom_list]
            screen = [0.5 for i in self.atom_list]
            for i, atom in enumerate(self.atom_list):
                if atom.element == 6:

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def __init__(self, file, periodicBoxVectors=None, unitCellDimensions=None, includeDir=None, defines=None):
        """Load a top file.

        Parameters
        ----------
        file : str
            the name of the file to load
        periodicBoxVectors : tuple of Vec3=None
            the vectors defining the periodic box
        unitCellDimensions : Vec3=None
            the dimensions of the crystallographic unit cell.  For
            non-rectangular unit cells, specify periodicBoxVectors instead.
        includeDir : string=None
            A directory in which to look for other files included from the
            top file. If not specified, we will attempt to locate a gromacs
            installation on your system. When gromacs is installed in
            /usr/local, this will resolve to /usr/local/gromacs/share/gromacs/top
        defines : dict={}
            preprocessor definitions that should be predefined when parsing the file
         """
        if includeDir is None:
            includeDir = _defaultGromacsIncludeDir()
        self._includeDirs = (os.path.dirname(file), includeDir)
        # Most of the gromacs water itp files for different forcefields,
        # unless the preprocessor #define FLEXIBLE is given, don't define
        # bonds between the water hydrogen and oxygens, but only give the
        # constraint distances and exclusions.
        self._defines = OrderedDict()
        self._defines['FLEXIBLE'] = True
        self._genpairs = True
        if defines is not None:
            for define, value in defines.iteritems():
                self._defines[define] = value

        # Parse the file.

        self._currentCategory = None
        self._ifStack = []
        self._elseStack = []
        self._moleculeTypes = {}
        self._molecules = []
        self._currentMoleculeType = None
        self._atomTypes = {}
        self._bondTypes= {}
        self._angleTypes = {}
        self._dihedralTypes = {}
        self._implicitTypes = {}
        self._pairTypes = {}
        self._cmapTypes = {}
        self._processFile(file)

        # Create the Topology from it.

        top = Topology()
        ## The Topology read from the prmtop file
        self.topology = top
        if periodicBoxVectors is not None:
            if unitCellDimensions is not None:
                raise ValueError("specify either periodicBoxVectors or unitCellDimensions, but not both")
            top.setPeriodicBoxVectors(periodicBoxVectors)
        else:
            top.setUnitCellDimensions(unitCellDimensions)
        PDBFile._loadNameReplacementTables()
        for moleculeName, moleculeCount in self._molecules:
            if moleculeName not in self._moleculeTypes:
                raise ValueError("Unknown molecule type: "+moleculeName)
            moleculeType = self._moleculeTypes[moleculeName]
            if moleculeCount > 0 and moleculeType.has_virtual_sites:
                raise ValueError('Virtual sites not yet supported by Gromacs parsers')

            # Create the specified number of molecules of this type.

            for i in range(moleculeCount):
                atoms = []
                lastResidue = None
                c = top.addChain()
                for index, fields in enumerate(moleculeType.atoms):
                    resNumber = fields[2]
                    if resNumber != lastResidue:
                        lastResidue = resNumber
                        resName = fields[3]
                        if resName in PDBFile._residueNameReplacements:
                            resName = PDBFile._residueNameReplacements[resName]
                        r = top.addResidue(resName, c)
                        if resName in PDBFile._atomNameReplacements:
                            atomReplacements = PDBFile._atomNameReplacements[resName]
                        else:
                            atomReplacements = {}
                    atomName = fields[4]
                    if atomName in atomReplacements:
                        atomName = atomReplacements[atomName]

                    # Try to guess the element.

                    upper = atomName.upper()
                    if upper.startswith('CL'):
                        element = elem.chlorine
                    elif upper.startswith('NA'):
                        element = elem.sodium
                    elif upper.startswith('MG'):
#.........这里部分代码省略.........

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def __init__(self, file, unitCellDimensions=None, includeDir='/usr/local/gromacs/share/gromacs/top', defines={}):
        """Load a top file.

        Parameters:
         - file (string) the name of the file to load
         - unitCellDimensions (Vec3=None) the dimensions of the crystallographic unit cell
         - includeDir (string=/usr/local/gromacs/share/gromacs/top) a directory in which to look for other files
           included from the top file
         - defines (map={}) preprocessor definitions that should be predefined when parsing the file
         """
        self._includeDirs = (os.path.dirname(file), includeDir)
        self._defines = defines

        # Parse the file.

        self._currentCategory = None
        self._ifStack = []
        self._moleculeTypes = {}
        self._molecules = []
        self._currentMoleculeType = None
        self._atomTypes = {}
        self._bondTypes= {}
        self._angleTypes = {}
        self._dihedralTypes = {}
        self._implicitTypes = {}
        self._pairTypes = {}
        self._cmapTypes = {}
        self._processFile(file)

        # Create the Topology from it.

        top = Topology()
        ## The Topology read from the prmtop file
        self.topology = top
        top.setUnitCellDimensions(unitCellDimensions)
        PDBFile._loadNameReplacementTables()
        for moleculeName, moleculeCount in self._molecules:
            if moleculeName not in self._moleculeTypes:
                raise ValueError("Unknown molecule type: "+moleculeName)
            moleculeType = self._moleculeTypes[moleculeName]

            # Create the specified number of molecules of this type.

            for i in range(moleculeCount):
                atoms = []
                lastResidue = None
                c = top.addChain()
                for index, fields in enumerate(moleculeType.atoms):
                    resNumber = fields[2]
                    if resNumber != lastResidue:
                        lastResidue = resNumber
                        resName = fields[3]
                        if resName in PDBFile._residueNameReplacements:
                            resName = PDBFile._residueNameReplacements[resName]
                        r = top.addResidue(resName, c)
                        if resName in PDBFile._atomNameReplacements:
                            atomReplacements = PDBFile._atomNameReplacements[resName]
                        else:
                            atomReplacements = {}
                    atomName = fields[4]
                    if atomName in atomReplacements:
                        atomName = atomReplacements[atomName]

                    # Try to guess the element.

                    upper = atomName.upper()
                    if upper.startswith('CL'):
                        element = elem.chlorine
                    elif upper.startswith('NA'):
                        element = elem.sodium
                    elif upper.startswith('MG'):
                        element = elem.magnesium
                    else:
                        try:
                            element = elem.get_by_symbol(atomName[0])
                        except KeyError:
                            element = None
                    atoms.append(top.addAtom(atomName, element, r))

                # Add bonds to the topology

                for fields in moleculeType.bonds:
                    top.addBond(atoms[int(fields[0])-1], atoms[int(fields[1])-1])

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def addExtraParticles(self, forcefield):
        """Add missing extra particles to the model that are required by a force field.

        Some force fields use "extra particles" that do not represent actual atoms, but still need to be included in
        the System.  Examples include lone pairs, Drude particles, and the virtual sites used in some water models
        to adjust the charge distribution.  Extra particles can be recognized by the fact that their element is None.

        This method is primarily used to add extra particles, but it can also remove them.  It tries to match every
        residue in the Topology to a template in the force field.  If there is no match, it will both add and remove
        extra particles as necessary to make it match.

        Parameters:
         - forcefield (ForceField) the ForceField defining what extra particles should be present
        """
        # Create copies of all residue templates that have had all extra points removed.

        templatesNoEP = {}
        for resName, template in forcefield._templates.iteritems():
            if any(atom.element is None for atom in template.atoms):
                index = 0
                newIndex = {}
                newTemplate = ForceField._TemplateData(resName)
                for i, atom in enumerate(template.atoms):
                    if atom.element is not None:
                        newIndex[i] = index
                        index += 1
                        newTemplate.atoms.append(ForceField._TemplateAtomData(atom.name, atom.type, atom.element))
                for b1, b2 in template.bonds:
                    if b1 in newIndex and b2 in newIndex:
                        newTemplate.bonds.append((newIndex[b1], newIndex[b2]))
                        newTemplate.atoms[newIndex[b1]].bondedTo.append(newIndex[b2])
                        newTemplate.atoms[newIndex[b2]].bondedTo.append(newIndex[b1])
                for b in template.externalBonds:
                    if b in newIndex:
                        newTemplate.externalBonds.append(newIndex[b])
                templatesNoEP[template] = newTemplate

        # Record which atoms are bonded to each other atom, with and without extra particles.

        bondedToAtom = []
        bondedToAtomNoEP = []
        for atom in self.topology.atoms():
            bondedToAtom.append(set())
            bondedToAtomNoEP.append(set())
        for atom1, atom2 in self.topology.bonds():
            bondedToAtom[atom1.index].add(atom2.index)
            bondedToAtom[atom2.index].add(atom1.index)
            if atom1.element is not None and atom2.element is not None:
                bondedToAtomNoEP[atom1.index].add(atom2.index)
                bondedToAtomNoEP[atom2.index].add(atom1.index)

        # If the force field has a DrudeForce, record the types of Drude particles and their parents since we'll
        # need them for picking particle positions.

        drudeTypeMap = {}
        for force in forcefield._forces:
            if isinstance(force, DrudeGenerator):
                for type in force.typeMap:
                    drudeTypeMap[type] = force.typeMap[type][0]

        # Create the new Topology.

        newTopology = Topology()
        newTopology.setUnitCellDimensions(deepcopy(self.topology.getUnitCellDimensions()))
        newAtoms = {}
        newPositions = []*nanometer
        for chain in self.topology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)

                # Look for a matching template.

                matchFound = False
                signature = _createResidueSignature([atom.element for atom in residue.atoms()])
                if signature in forcefield._templateSignatures:
                    for t in forcefield._templateSignatures[signature]:
                        if _matchResidue(residue, t, bondedToAtom) is not None:
                            matchFound = True
                if matchFound:
                    # Just copy the residue over.

                    for atom in residue.atoms():
                        newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
                        newAtoms[atom] = newAtom
                        newPositions.append(deepcopy(self.positions[atom.index]))
                else:
                    # There's no matching template.  Try to find one that matches based on everything except
                    # extra points.

                    template = None
                    residueNoEP = Residue(residue.name, residue.index, residue.chain)
                    residueNoEP._atoms = [atom for atom in residue.atoms() if atom.element is not None]
                    if signature in forcefield._templateSignatures:
                        for t in forcefield._templateSignatures[signature]:
                            if t in templatesNoEP:
                                matches = _matchResidue(residueNoEP, templatesNoEP[t], bondedToAtomNoEP)
                                if matches is not None:
                                    template = t;
                                    # Record the corresponding atoms.
#.........这里部分代码省略.........

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def addHydrogens(self, forcefield, pH=7.0, variants=None, platform=None):
        """Add missing hydrogens to the model.

        Some residues can exist in multiple forms depending on the pH and properties of the local environment.  These
        variants differ in the presence or absence of particular hydrogens.  In particular, the following variants
        are supported:

        Aspartic acid:
            ASH: Neutral form with a hydrogen on one of the delta oxygens
            ASP: Negatively charged form without a hydrogen on either delta oxygen

        Cysteine:
            CYS: Neutral form with a hydrogen on the sulfur
            CYX: No hydrogen on the sulfur (either negatively charged, or part of a disulfide bond)

        Glutamic acid:
            GLH: Neutral form with a hydrogen on one of the epsilon oxygens
            GLU: Negatively charged form without a hydrogen on either epsilon oxygen

        Histidine:
            HID: Neutral form with a hydrogen on the ND1 atom
            HIE: Neutral form with a hydrogen on the NE2 atom
            HIP: Positively charged form with hydrogens on both ND1 and NE2

        Lysine:
            LYN: Neutral form with two hydrogens on the zeta nitrogen
            LYS: Positively charged form with three hydrogens on the zeta nitrogen

        The variant to use for each residue is determined by the following rules:

        1. The most common variant at the specified pH is selected.
        2. Any Cysteine that participates in a disulfide bond uses the CYX variant regardless of pH.
        3. For a neutral Histidine residue, the HID or HIE variant is selected based on which one forms a better hydrogen bond.

        You can override these rules by explicitly specifying a variant for any residue.  Also keep in mind that this
        function will only add hydrogens.  It will never remove ones that are already present in the model, regardless
        of the specified pH.

        Definitions for standard amino acids and nucleotides are built in.  You can call loadHydrogenDefinitions() to load
        additional definitions for other residue types.

        Parameters:
         - forcefield (ForceField) the ForceField to use for determining the positions of hydrogens
         - pH (float=7.0) the pH based on which to select variants
         - variants (list=None) an optional list of variants to use.  If this is specified, its length must equal the number
           of residues in the model.  variants[i] is the name of the variant to use for residue i (indexed starting at 0).
           If an element is None, the standard rules will be followed to select a variant for that residue.
         - platform (Platform=None) the Platform to use when computing the hydrogen atom positions.  If this is None,
           the default Platform will be used.
        Returns: a list of what variant was actually selected for each residue, in the same format as the variants parameter
        """
        # Check the list of variants.

        residues = list(self.topology.residues())
        if variants is not None:
            if len(variants) != len(residues):
                raise ValueError("The length of the variants list must equal the number of residues")
        else:
            variants = [None]*len(residues)
        actualVariants = [None]*len(residues)

        # Load the residue specifications.

        if not Modeller._hasLoadedStandardHydrogens:
            Modeller.loadHydrogenDefinitions(os.path.join(os.path.dirname(__file__), 'data', 'hydrogens.xml'))

        # Make a list of atoms bonded to each atom.

        bonded = {}
        for atom in self.topology.atoms():
            bonded[atom] = []
        for atom1, atom2 in self.topology.bonds():
            bonded[atom1].append(atom2)
            bonded[atom2].append(atom1)

        # Define a function that decides whether a set of atoms form a hydrogen bond, using fairly tolerant criteria.

        def isHbond(d, h, a):
            if norm(d-a) > 0.35*nanometer:
                return False
            deltaDH = h-d
            deltaHA = a-h
            deltaDH /= norm(deltaDH)
            deltaHA /= norm(deltaHA)
            return acos(dot(deltaDH, deltaHA)) < 50*degree

        # Loop over residues.

        newTopology = Topology()
        newTopology.setUnitCellDimensions(deepcopy(self.topology.getUnitCellDimensions()))
        newAtoms = {}
        newPositions = []*nanometer
        newIndices = []
        acceptors = [atom for atom in self.topology.atoms() if atom.element in (elem.oxygen, elem.nitrogen)]
        for chain in self.topology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)
                isNTerminal = (residue == chain._residues[0])
                isCTerminal = (residue == chain._residues[-1])
#.........这里部分代码省略.........

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def addSolvent(self, forcefield, model='tip3p', boxSize=None, padding=None, positiveIon='Na+', negativeIon='Cl-', ionicStrength=0*molar):
        """Add solvent (both water and ions) to the model to fill a rectangular box.

        The algorithm works as follows:
        1. Water molecules are added to fill the box.
        2. Water molecules are removed if their distance to any solute atom is less than the sum of their van der Waals radii.
        3. If the solute is charged, enough positive or negative ions are added to neutralize it.  Each ion is added by
           randomly selecting a water molecule and replacing it with the ion.
        4. Ion pairs are added to give the requested total ionic strength.

        The box size can be specified in three ways.  First, you can explicitly give a box size to use.  Alternatively, you can
        give a padding distance.  The largest dimension of the solute (along the x, y, or z axis) is determined, and a cubic
        box of size (largest dimension)+2*padding is used.  Finally, if neither a box size nor a padding distance is specified,
        the existing Topology's unit cell dimensions are used.

        Parameters:
         - forcefield (ForceField) the ForceField to use for determining van der Waals radii and atomic charges
         - model (string='tip3p') the water model to use.  Supported values are 'tip3p', 'spce', 'tip4pew', and 'tip5p'.
         - boxSize (Vec3=None) the size of the box to fill with water
         - padding (distance=None) the padding distance to use
         - positiveIon (string='Na+') the type of positive ion to add.  Allowed values are 'Cs+', 'K+', 'Li+', 'Na+', and 'Rb+'
         - negativeIon (string='Cl-') the type of negative ion to add.  Allowed values are 'Cl-', 'Br-', 'F-', and 'I-'. Be aware
           that not all force fields support all ion types.
         - ionicString (concentration=0*molar) the total concentration of ions (both positive and negative) to add.  This
           does not include ions that are added to neutralize the system.
        """
        # Pick a unit cell size.

        if boxSize is not None:
            if is_quantity(boxSize):
                boxSize = boxSize.value_in_unit(nanometer)
            box = Vec3(boxSize[0], boxSize[1], boxSize[2])*nanometer
        elif padding is not None:
            maxSize = max(max((pos[i] for pos in self.positions))-min((pos[i] for pos in self.positions)) for i in range(3))
            box = (maxSize+2*padding)*Vec3(1, 1, 1)
        else:
            box = self.topology.getUnitCellDimensions()
            if box is None:
                raise ValueError('Neither the box size nor padding was specified, and the Topology does not define unit cell dimensions')
        box = box.value_in_unit(nanometer)
        invBox = Vec3(1.0/box[0], 1.0/box[1], 1.0/box[2])

        # Identify the ion types.

        posIonElements = {'Cs+':elem.cesium, 'K+':elem.potassium, 'Li+':elem.lithium, 'Na+':elem.sodium, 'Rb+':elem.rubidium}
        negIonElements = {'Cl-':elem.chlorine, 'Br-':elem.bromine, 'F-':elem.fluorine, 'I-':elem.iodine}
        if positiveIon not in posIonElements:
            raise ValueError('Illegal value for positive ion: %s' % positiveIon)
        if negativeIon not in negIonElements:
            raise ValueError('Illegal value for negative ion: %s' % negativeIon)
        positiveElement = posIonElements[positiveIon]
        negativeElement = negIonElements[negativeIon]

        # Load the pre-equilibrated water box.

        vdwRadiusPerSigma = 0.5612310241546864907
        if model == 'tip3p':
            waterRadius = 0.31507524065751241*vdwRadiusPerSigma
        elif model == 'spce':
            waterRadius = 0.31657195050398818*vdwRadiusPerSigma
        elif model == 'tip4pew':
            waterRadius = 0.315365*vdwRadiusPerSigma
        elif model == 'tip5p':
            waterRadius = 0.312*vdwRadiusPerSigma
        else:
            raise ValueError('Unknown water model: %s' % model)
        pdb = PDBFile(os.path.join(os.path.dirname(__file__), 'data', model+'.pdb'))
        pdbTopology = pdb.getTopology()
        pdbPositions = pdb.getPositions().value_in_unit(nanometer)
        pdbResidues = list(pdbTopology.residues())
        pdbBoxSize = pdbTopology.getUnitCellDimensions().value_in_unit(nanometer)

        # Have the ForceField build a System for the solute from which we can determine van der Waals radii.

        system = forcefield.createSystem(self.topology)
        nonbonded = None
        for i in range(system.getNumForces()):
            if isinstance(system.getForce(i), NonbondedForce):
                nonbonded = system.getForce(i)
        if nonbonded is None:
            raise ValueError('The ForceField does not specify a NonbondedForce')
        cutoff = [nonbonded.getParticleParameters(i)[1].value_in_unit(nanometer)*vdwRadiusPerSigma+waterRadius for i in range(system.getNumParticles())]
        waterCutoff = waterRadius
        if len(cutoff) == 0:
            maxCutoff = waterCutoff
        else:
            maxCutoff = max(waterCutoff, max(cutoff))

        # Copy the solute over.

        newTopology = Topology()
        newTopology.setUnitCellDimensions(box)
        newAtoms = {}
        newPositions = []*nanometer
        for chain in self.topology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)
                for atom in residue.atoms():
                    newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
#.........这里部分代码省略.........

# 需要导入模块: from simtk.openmm.app import Topology [as 别名]
# 或者: from simtk.openmm.app.Topology import setUnitCellDimensions [as 别名]
    def convertWater(self, model='tip3p'):
        """Convert all water molecules to a different water model.

        Parameters:
         - model (string='tip3p') the water model to convert to.  Supported values are 'tip3p', 'spce', 'tip4pew', and 'tip5p'.
        
        @deprecated Use addExtraParticles() instead.  It performs the same function but in a more general way.
        """
        if model in ('tip3p', 'spce'):
            sites = 3
        elif model == 'tip4pew':
            sites = 4
        elif model == 'tip5p':
            sites = 5
        else:
            raise ValueError('Unknown water model: %s' % model)
        newTopology = Topology()
        newTopology.setUnitCellDimensions(deepcopy(self.topology.getUnitCellDimensions()))
        newAtoms = {}
        newPositions = []*nanometer
        for chain in self.topology.chains():
            newChain = newTopology.addChain()
            for residue in chain.residues():
                newResidue = newTopology.addResidue(residue.name, newChain)
                if residue.name == "HOH":
                    # Copy the oxygen and hydrogens
                    oatom = [atom for atom in residue.atoms() if atom.element == elem.oxygen]
                    hatoms = [atom for atom in residue.atoms() if atom.element == elem.hydrogen]
                    if len(oatom) != 1 or len(hatoms) != 2:
                        raise ValueError('Illegal water molecule (residue %d): contains %d oxygen(s) and %d hydrogen(s)' % (residue.index, len(oatom), len(hatoms)))
                    o = newTopology.addAtom(oatom[0].name, oatom[0].element, newResidue)
                    h1 = newTopology.addAtom(hatoms[0].name, hatoms[0].element, newResidue)
                    h2 = newTopology.addAtom(hatoms[1].name, hatoms[1].element, newResidue)
                    newAtoms[oatom[0]] = o
                    newAtoms[hatoms[0]] = h1
                    newAtoms[hatoms[1]] = h2
                    po = deepcopy(self.positions[oatom[0].index])
                    ph1 = deepcopy(self.positions[hatoms[0].index])
                    ph2 = deepcopy(self.positions[hatoms[1].index])
                    newPositions.append(po)
                    newPositions.append(ph1)
                    newPositions.append(ph2)

                    # Add virtual sites.

                    if sites == 4:
                        newTopology.addAtom('M', None, newResidue)
                        newPositions.append(0.786646558*po + 0.106676721*ph1 + 0.106676721*ph2)
                    elif sites == 5:
                        newTopology.addAtom('M1', None, newResidue)
                        newTopology.addAtom('M2', None, newResidue)
                        v1 = (ph1-po).value_in_unit(nanometer)
                        v2 = (ph2-po).value_in_unit(nanometer)
                        cross = Vec3(v1[1]*v2[2]-v1[2]*v2[1], v1[2]*v2[0]-v1[0]*v2[2], v1[0]*v2[1]-v1[1]*v2[0])
                        newPositions.append(po - (0.34490826*v1 - 0.34490826*v2 - 6.4437903*cross)*nanometer)
                        newPositions.append(po - (0.34490826*v1 - 0.34490826*v2 + 6.4437903*cross)*nanometer)
                else:
                    # Just copy the residue over.
                    for atom in residue.atoms():
                        newAtom = newTopology.addAtom(atom.name, atom.element, newResidue)
                        newAtoms[atom] = newAtom
                        newPositions.append(deepcopy(self.positions[atom.index]))
        for bond in self.topology.bonds():
            if bond[0] in newAtoms and bond[1] in newAtoms:
                newTopology.addBond(newAtoms[bond[0]], newAtoms[bond[1]])
        self.topology = newTopology
        self.positions = newPositions