AmoebaPiTorsionForce¶
-
class
OpenMM
::
AmoebaPiTorsionForce
¶ This class implements the Amoeba pi-torsion interaction.
To use it, create an
AmoebaPiTorsionForce
object then calladdPiTorsion()
once for each torsion. After a torsion has been added, you can modify its force field parameters by callingsetPiTorsionParameters()
. This will have no effect on Contexts that already exist unless you callupdateParametersInContext()
.Methods
Create an
AmoebaPiTorsionForce
.Get the number of pi torsion terms in the potential function
Add a torsion term to the force field.
Get the force field parameters for a torsion term.
Set the force field parameters for a pi torsion term.
Update the per-torsion parameters in a
Context
to match those stored in thisForce
object.Set whether this force should apply periodic boundary conditions when calculating displacements.
Returns whether or not this force makes use of periodic boundary conditions.
-
AmoebaPiTorsionForce
()¶ Create an
AmoebaPiTorsionForce()
.
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int
getNumPiTorsions
() const¶ Get the number of pi torsion terms in the potential function
-
int
addPiTorsion
(int particle1, int particle2, int particle3, int particle4, int particle5, int particle6, double k)¶ Add a torsion term to the force field.
- Parameters
particle1 – the index of the first particle connected by the torsion
particle2 – the index of the second particle connected by the torsion
particle3 – the index of the third particle connected by the torsion
particle4 – the index of the fourth particle connected by the torsion
particle5 – the index of the fifth particle connected by the torsion
particle6 – the index of the sixth particle connected by the torsion
k – the force constant for the torsion
- Returns
the index of the torsion that was added
-
void
getPiTorsionParameters
(int index, int &particle1, int &particle2, int &particle3, int &particle4, int &particle5, int &particle6, double &k) const¶ Get the force field parameters for a torsion term.
- Parameters
index – the index of the torsion for which to get parameters
particle1 – [out] the index of the first particle connected by the torsion
particle2 – [out] the index of the second particle connected by the torsion
particle3 – [out] the index of the third particle connected by the torsion
particle4 – [out] the index of the fourth particle connected by the torsion
particle5 – [out] the index of the fifth particle connected by the torsion
particle6 – [out] the index of the sixth particle connected by the torsion
k – [out] the force constant for the torsion
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void
setPiTorsionParameters
(int index, int particle1, int particle2, int particle3, int particle4, int particle5, int particle6, double k)¶ Set the force field parameters for a pi torsion term.
- Parameters
index – the index of the torsion for which to set parameters
particle1 – the index of the first particle connected by the torsion
particle2 – the index of the second particle connected by the torsion
particle3 – the index of the third particle connected by the torsion
particle4 – the index of the fourth particle connected by the torsion
particle5 – the index of the fifth particle connected by the torsion
particle6 – the index of the sixth particle connected by the torsion
k – the force constant for the torsion
-
void
updateParametersInContext
(Context &context)¶ Update the per-torsion parameters in a
Context
to match those stored in thisForce
object. This method provides an efficient method to update certain parameters in an existingContext
without needing to reinitialize it. Simply callsetPiTorsionParameters()
to modify this object’s parameters, then callupdateParametersInContext()
to copy them over to theContext
.The only information this method updates is the values of per-torsion parameters. The set of particles involved in a torsion cannot be changed, nor can new torsions be added.
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void
setUsesPeriodicBoundaryConditions
(bool periodic)¶ Set whether this force should apply periodic boundary conditions when calculating displacements. Usually this is not appropriate for bonded forces, but there are situations when it can be useful.
-
bool
usesPeriodicBoundaryConditions
() const¶ Returns whether or not this force makes use of periodic boundary conditions.
- Returns
true if force uses PBC and false otherwise
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