AmoebaInPlaneAngleForce¶

class
OpenMM::
AmoebaInPlaneAngleForce
¶ This class implements an interaction at trigonal centers corresponding to the projected inplane angle bend energy between four particles. The interaction is defined by a 6th order polynomial in the angle between them. Only the quadratic term is set perangle. The coefficients of the higher order terms each have a single value that is set globally.
To use it, create an
AmoebaInPlaneAngleForce
object then calladdAngle()
once for each angle. After an angle has been added, you can modify its force field parameters by callingsetAngleParameters()
. This will have no effect on Contexts that already exist unless you callupdateParametersInContext()
.Methods
AmoebaInPlaneAngleForce
Create an AmoebaAngleForce
.getNumAngles
Get the number of inplane angle terms in the potential function setAmoebaGlobalInPlaneAngleCubic
Set the global cubic term getAmoebaGlobalInPlaneAngleCubic
Get the global cubic term setAmoebaGlobalInPlaneAngleQuartic
Set the global quartic term getAmoebaGlobalInPlaneAngleQuartic
Get the global quartic term setAmoebaGlobalInPlaneAnglePentic
Set the global pentic term getAmoebaGlobalInPlaneAnglePentic
Get the global pentic term setAmoebaGlobalInPlaneAngleSextic
Set the global sextic term getAmoebaGlobalInPlaneAngleSextic
Get the global sextic term addAngle
Add an angle term to the force field. getAngleParameters
Get the force field parameters for an angle term. setAngleParameters
Set the force field parameters for an angle term. updateParametersInContext
Update the perangle parameters in a Context
to match those stored in thisForce
object.setUsesPeriodicBoundaryConditions
Set whether this force should apply periodic boundary conditions when calculating displacements. usesPeriodicBoundaryConditions
Returns whether or not this force makes use of periodic boundary conditions. 
AmoebaInPlaneAngleForce
()¶ Create an
AmoebaAngleForce
.

int
getNumAngles
() const¶ Get the number of inplane angle terms in the potential function

void
setAmoebaGlobalInPlaneAngleCubic
(double cubicK)¶ Set the global cubic term
Parameters:  cubicK – the cubic force constant for the angle

double
getAmoebaGlobalInPlaneAngleCubic
() const¶ Get the global cubic term
Returns: global cubicK term

void
setAmoebaGlobalInPlaneAngleQuartic
(double quarticK)¶ Set the global quartic term
Parameters:  quarticK – the quartic force constant for the angle

double
getAmoebaGlobalInPlaneAngleQuartic
() const¶ Get the global quartic term
Returns: global quartic term

void
setAmoebaGlobalInPlaneAnglePentic
(double penticK)¶ Set the global pentic term
Parameters:  penticK – the pentic force constant for the angle

double
getAmoebaGlobalInPlaneAnglePentic
() const¶ Get the global pentic term
Returns: global penticK term

void
setAmoebaGlobalInPlaneAngleSextic
(double sexticK)¶ Set the global sextic term
Parameters:  sexticK – the sextic force constant for the angle

double
getAmoebaGlobalInPlaneAngleSextic
() const¶ Get the global sextic term
Returns: global sextic term

int
addAngle
(int particle1, int particle2, int particle3, int particle4, double length, double quadraticK)¶ Add an angle term to the force field.
Parameters:  particle1 – the index of the first particle connected by the angle
 particle2 – the index of the second particle connected by the angle
 particle3 – the index of the third particle connected by the angle
 particle4 – the index of the fourth particle connected by the angle
 length – the equilibrium angle, measured in radians
 quadraticK – the quadratic force constant for the angle measured in kJ/mol/radian^2
Returns: the index of the angle that was added

void
getAngleParameters
(int index, int &particle1, int &particle2, int &particle3, int &particle4, double &length, double &quadraticK) const¶ Get the force field parameters for an angle term.
Parameters:  index – the index of the angle for which to get parameters
 particle1 – [out] the index of the first particle connected by the angle
 particle2 – [out] the index of the second particle connected by the angle
 particle3 – [out] the index of the third particle connected by the angle
 particle4 – [out] the index of the fourth particle connected by the angle
 length – [out] the equilibrium angle, measured in radians
 quadraticK – [out] the quadratic force constant for the angle measured in kJ/mol/radian^2

void
setAngleParameters
(int index, int particle1, int particle2, int particle3, int particle4, double length, double quadraticK)¶ Set the force field parameters for an angle term.
Parameters:  index – the index of the angle for which to set parameters
 particle1 – the index of the first particle connected by the angle
 particle2 – the index of the second particle connected by the angle
 particle3 – the index of the third particle connected by the angle
 particle4 – the index of the fourth particle connected by the angle
 length – the equilibrium angle, measured in radians
 quadraticK – the quadratic force constant for the angle, measured in kJ/mol/radian^2

void
updateParametersInContext
(Context &context)¶ Update the perangle 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 callsetAngleParameters()
to modify this object’s parameters, then callupdateParametersInContext()
to copy them over to theContext
.The only information this method updates is the values of perangle parameters. The set of particles involved in an angle cannot be changed, nor can new angles be added.

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
