javax.robotics.ode
Interface Solver

All Known Implementing Classes:

Euler, Heun, RungeKutta4th

public interface Solver

This class is an interface for differents numerical integration methods of first order differential equations.
The implementation of a solver could be done writing:

 ...
 public MyODESolver implements DerivableFunction
 {
      ...
      RVector x0 = new RVector(n);
      // Creating the solver
      Solver mySolver = Euler(0.1, // time interval integration
                              x0,  // initial condition 
                              this // function xDot is passed to Solver
                             );
      ...
      
      // integration at time t+dt of x' = f(x) implemented by xDot(x) function
      x_dt = mySolver.step(x_t);
      
      // current time integration
      t_dt = mySolver.getTime();
      
      // current integrated value
      x_dt = mySolver.getLastValue();
      
      ...
      
      // implementation of x' = f(x)
      public RVector xDot(RVector x)
      {
          ...
          // code to calculate x' = f(x)
          ...
          return xdot;
      }
 }
 

Since:

1.0.0

Version:

09/11/2005

Author:

Carmine Lia

Field Summary

static double

startTime

Method Summary

RVector	getInitialCondition() Gets the initial condition for position x(0).
RVector	getLastValue() Gets the current value of position x computed by step function.
double	getSampleTime() Gets the interval of integration.
double	getTime() Gets current time of integration.
void	setInitialCondition(RVector initialCondition) Sets the initial condition for position x(0) = x0.
void	setSampleTime(double dt) Sets the interval of integration.
void	step(RVector x) Computes step integration from time t to t+dt of x' = f(x).

Field Detail

startTime

static final double startTime

See Also:

Constant Field Values

Method Detail

setSampleTime

void setSampleTime(double dt)

Sets the interval of integration.

Parameters:

dt - interval [sec]

getSampleTime

double getSampleTime()

Gets the interval of integration.

Returns:

the dt interval [sec]

getTime

double getTime()

Gets current time of integration.

Returns:

the current time [sec]

setInitialCondition

void setInitialCondition(RVector initialCondition)

Sets the initial condition for position x(0) = x₀.

Parameters:

initialCondition -

getInitialCondition

RVector getInitialCondition()

Gets the initial condition for position x(0).

Returns:

the initialCondition

getLastValue

RVector getLastValue()

Gets the current value of position x computed by step function.

Returns:

the current position.

step

void step(RVector x)

Computes step integration from time t to t+dt of x' = f(x). The params last value position is modified.

Parameters:

x - argument of f(x)