org.apache.commons.math.ode.nonstiff
Class RungeKuttaIntegrator
java.lang.Object
org.apache.commons.math.ode.AbstractIntegrator
org.apache.commons.math.ode.nonstiff.RungeKuttaIntegrator
- All Implemented Interfaces:
- FirstOrderIntegrator, ODEIntegrator
- Direct Known Subclasses:
- ClassicalRungeKuttaIntegrator, EulerIntegrator, GillIntegrator, MidpointIntegrator, ThreeEighthesIntegrator
public abstract class RungeKuttaIntegrator
- extends AbstractIntegrator
This class implements the common part of all fixed step Runge-Kutta
integrators for Ordinary Differential Equations.
These methods are explicit Runge-Kutta methods, their Butcher
arrays are as follows :
0 |
c2 | a21
c3 | a31 a32
... | ...
cs | as1 as2 ... ass-1
|--------------------------
| b1 b2 ... bs-1 bs
- Since:
- 1.2
- Version:
- $Revision: 785473 $ $Date: 2009-06-17 00:02:35 -0400 (Wed, 17 Jun 2009) $
- See Also:
EulerIntegrator
,
ClassicalRungeKuttaIntegrator
,
GillIntegrator
,
MidpointIntegrator
Constructor Summary |
protected |
RungeKuttaIntegrator(String name,
double[] c,
double[][] a,
double[] b,
org.apache.commons.math.ode.nonstiff.RungeKuttaStepInterpolator prototype,
double step)
Simple constructor. |
Methods inherited from class org.apache.commons.math.ode.AbstractIntegrator |
addEndTimeChecker, addEventHandler, addStepHandler, clearEventHandlers, clearStepHandlers, computeDerivatives, getCurrentSignedStepsize, getCurrentStepStart, getEvaluations, getEventHandlers, getMaxEvaluations, getName, getStepHandlers, requiresDenseOutput, resetEvaluations, sanityChecks, setEquations, setMaxEvaluations |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
RungeKuttaIntegrator
protected RungeKuttaIntegrator(String name,
double[] c,
double[][] a,
double[] b,
org.apache.commons.math.ode.nonstiff.RungeKuttaStepInterpolator prototype,
double step)
- Simple constructor.
Build a Runge-Kutta integrator with the given
step. The default step handler does nothing.
- Parameters:
name
- name of the methodc
- time steps from Butcher array (without the first zero)a
- internal weights from Butcher array (without the first empty row)b
- propagation weights for the high order method from Butcher arrayprototype
- prototype of the step interpolator to usestep
- integration step
integrate
public double integrate(FirstOrderDifferentialEquations equations,
double t0,
double[] y0,
double t,
double[] y)
throws DerivativeException,
IntegratorException
- Integrate the differential equations up to the given time.
This method solves an Initial Value Problem (IVP).
Since this method stores some internal state variables made
available in its public interface during integration (ODEIntegrator.getCurrentSignedStepsize()
), it is not thread-safe.
- Parameters:
equations
- differential equations to integratet0
- initial timey0
- initial value of the state vector at t0t
- target time for the integration
(can be set to a value smaller than t0
for backward integration)y
- placeholder where to put the state vector at each successful
step (and hence at the end of integration), can be the same object as y0
- Returns:
- stop time, will be the same as target time if integration reached its
target, but may be different if some
EventHandler
stops it at some point.
- Throws:
DerivativeException
- this exception is propagated to the caller if
the underlying user function triggers one
IntegratorException
- if the integrator cannot perform integration
Copyright © 2003-2009 Apache Software Foundation. All Rights Reserved.