HarmonicAngleForce¶
-
class
OpenMM
::
HarmonicAngleForce
¶ This class implements an interaction between groups of three particles that varies harmonically with the angle between them. To use it, create a
HarmonicAngleForce
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
Create a
HarmonicAngleForce
.Get the number of harmonic bond angle terms in the potential function
Add an angle term to the force field.
Get the force field parameters for an angle term.
Set the force field parameters for an angle term.
Update the per-angle 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.
-
HarmonicAngleForce
()¶ Create a
HarmonicAngleForce()
.
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int
getNumAngles
() const¶ Get the number of harmonic bond angle terms in the potential function
-
int
addAngle
(int particle1, int particle2, int particle3, double angle, double k)¶ Add an angle term to the force field.
- Parameters
particle1 – the index of the first particle forming the angle
particle2 – the index of the second particle forming the angle
particle3 – the index of the third particle forming the angle
angle – the equilibrium angle, measured in radians
k – the harmonic 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, double &angle, double &k) 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 forming the angle
particle2 – [out] the index of the second particle forming the angle
particle3 – [out] the index of the third particle forming the angle
angle – [out] the equilibrium angle, measured in radians
k – [out] the harmonic force constant for the angle, measured in kJ/mol/radian^2
-
void
setAngleParameters
(int index, int particle1, int particle2, int particle3, double angle, double k)¶ 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 forming the angle
particle2 – the index of the second particle forming the angle
particle3 – the index of the third particle forming the angle
angle – the equilibrium angle, measured in radians
k – the harmonic force constant for the angle, measured in kJ/mol/radian^2
-
void
updateParametersInContext
(Context &context)¶ Update the per-angle 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 per-angle parameters. The set of particles involved in a angle cannot be changed, nor can new angles 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.
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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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