Class RungeKuttaIntegrator

  extended by org.apache.commons.math3.ode.AbstractIntegrator
      extended by org.apache.commons.math3.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

$Id: 1416643 2012-12-03 19:37:14Z tn $
See Also:
EulerIntegrator, ClassicalRungeKuttaIntegrator, GillIntegrator, MidpointIntegrator

Field Summary
Fields inherited from class org.apache.commons.math3.ode.AbstractIntegrator
isLastStep, resetOccurred, stepHandlers, stepSize, stepStart
Constructor Summary
protected RungeKuttaIntegrator(String name, double[] c, double[][] a, double[] b, org.apache.commons.math3.ode.nonstiff.RungeKuttaStepInterpolator prototype, double step)
          Simple constructor.
Method Summary
 void integrate(ExpandableStatefulODE equations, double t)
          Integrate a set of differential equations up to the given time.
Methods inherited from class org.apache.commons.math3.ode.AbstractIntegrator
acceptStep, addEventHandler, addEventHandler, addStepHandler, clearEventHandlers, clearStepHandlers, computeDerivatives, getCurrentSignedStepsize, getCurrentStepStart, getEvaluations, getEventHandlers, getMaxEvaluations, getName, getStepHandlers, initIntegration, integrate, sanityChecks, setEquations, setMaxEvaluations, setStateInitialized
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


protected RungeKuttaIntegrator(String name,
                               double[] c,
                               double[][] a,
                               double[] b,
                               org.apache.commons.math3.ode.nonstiff.RungeKuttaStepInterpolator prototype,
                               double step)
Simple constructor. Build a Runge-Kutta integrator with the given step. The default step handler does nothing.

name - name of the method
c - 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 array
prototype - prototype of the step interpolator to use
step - integration step
Method Detail


public void integrate(ExpandableStatefulODE equations,
                      double t)
               throws NumberIsTooSmallException,
Integrate a set of differential equations up to the given time.

This method solves an Initial Value Problem (IVP).

The set of differential equations is composed of a main set, which can be extended by some sets of secondary equations. The set of equations must be already set up with initial time and partial states. At integration completion, the final time and partial states will be available in the same object.

Since this method stores some internal state variables made available in its public interface during integration (AbstractIntegrator.getCurrentSignedStepsize()), it is not thread-safe.

Specified by:
integrate in class AbstractIntegrator
equations - complete set of differential equations to integrate
t - target time for the integration (can be set to a value smaller than t0 for backward integration)
NumberIsTooSmallException - if integration step is too small
DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension
MaxCountExceededException - if the number of functions evaluations is exceeded
NoBracketingException - if the location of an event cannot be bracketed

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