# Integrator¶

class OpenMM::Integrator

An Integrator defines a method for simulating a System by integrating the equations of motion. This is an abstract class. Subclasses define particular integration methods.

Each Integrator object is bound to a particular Context which it integrates. This connection is specified by passing the Integrator as an argument to the constructor of the Context.

Methods

 Integrator ~Integrator getStepSize Get the size of each time step, in picoseconds. setStepSize Set the size of each time step, in picoseconds. getConstraintTolerance Get the distance tolerance within which constraints are maintained, as a fraction of the constrained distance. setConstraintTolerance Set the distance tolerance within which constraints are maintained, as a fraction of the constrained distance. step Advance a simulation through time by taking a series of time steps.
Integrator()
~Integrator()
double getStepSize() const

Get the size of each time step, in picoseconds. If this integrator uses variable time steps, the size of the most recent step is returned.

Returns: the step size, measured in ps
void setStepSize(double size)

Set the size of each time step, in picoseconds. If this integrator uses variable time steps, the effect of calling this method is undefined, and it may simply be ignored.

• size – the step size, measured in ps
double getConstraintTolerance() const

Get the distance tolerance within which constraints are maintained, as a fraction of the constrained distance.

void setConstraintTolerance(double tol)

Set the distance tolerance within which constraints are maintained, as a fraction of the constrained distance.

void step(int steps) = 0

Advance a simulation through time by taking a series of time steps.

• steps – the number of time steps to take