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Class JSci.maths.NumericalMath

java.lang.Object
   |
   +----JSci.maths.AbstractMath
           |
           +----JSci.maths.NumericalMath

public final class NumericalMath
extends AbstractMath
The numerical math library. This class cannot be subclassed or instantiated because all methods are static.


Method Index

 o differentiate(int, Mapping, double, double)
Numerical differentiation.
 o differentiate(NMapping, double[], double[])
Numerical differentiation in multiple dimensions.
 o euler(double[], Mapping, double)
Uses the Euler method to solve an ODE.
 o gaussian4(int, Mapping, double, double)
Numerical integration using the Gaussian integration formula (4 points).
 o gaussian8(int, Mapping, double, double)
Numerical integration using the Gaussian integration formula (8 points).
 o leapFrog(double[], Mapping, double)
Uses the Leap-Frog method to solve an ODE.
 o metropolis(double[], Mapping, double)
The Metropolis algorithm.
 o richardson(int, Mapping, double, double)
Numerical integration using the Richardson extrapolation.
 o rungeKutta2(double[], Mapping, double)
Uses the 2nd order Runge-Kutta method to solve an ODE.
 o rungeKutta4(double[], Mapping, double)
Uses the 4th order Runge-Kutta method to solve an ODE.
 o simpson(int, Mapping, double, double)
Numerical integration using Simpson's rule.
 o solveQuadratic(double, double, double)
Calculates the roots of the quadratic equation ax2+bx+c=0.
 o trapezium(int, Mapping, double, double)
Numerical integration using the trapezium rule.

Methods

 o solveQuadratic
 public static double[] solveQuadratic(double a,
                                       double b,
                                       double c)
Calculates the roots of the quadratic equation ax2+bx+c=0.

Returns:
an array containing the two roots
 o euler
 public static double[] euler(double y[],
                              Mapping func,
                              double dt)
Uses the Euler method to solve an ODE.

Parameters:
y - an array to be filled with y values, set y[0] to initial condition
func - dy/dt
dt - step size
Returns:
y
 o leapFrog
 public static double[] leapFrog(double y[],
                                 Mapping func,
                                 double dt)
Uses the Leap-Frog method to solve an ODE.

Parameters:
y - an array to be filled with y values, set y[0],y[1] to initial conditions
func - dy/dt
dt - step size
Returns:
y
 o rungeKutta2
 public static double[] rungeKutta2(double y[],
                                    Mapping func,
                                    double dt)
Uses the 2nd order Runge-Kutta method to solve an ODE.

Parameters:
y - an array to be filled with y values, set y[0] to initial condition
func - dy/dt
dt - step size
Returns:
y
 o rungeKutta4
 public static double[] rungeKutta4(double y[],
                                    Mapping func,
                                    double dt)
Uses the 4th order Runge-Kutta method to solve an ODE.

Parameters:
y - an array to be filled with y values, set y[0] to initial condition
func - dy/dt
dt - step size
Returns:
y
 o trapezium
 public static double trapezium(int N,
                                Mapping func,
                                double a,
                                double b)
Numerical integration using the trapezium rule.

Parameters:
N - the number of strips to use
func - a function
a - the first ordinate
b - the last ordinate
 o simpson
 public static double simpson(int N,
                              Mapping func,
                              double a,
                              double b)
Numerical integration using Simpson's rule.

Parameters:
N - the number of strip pairs to use
func - a function
a - the first ordinate
b - the last ordinate
 o richardson
 public static double richardson(int N,
                                 Mapping func,
                                 double a,
                                 double b)
Numerical integration using the Richardson extrapolation.

Parameters:
N - the number of strip pairs to use (lower value)
func - a function
a - the first ordinate
b - the last ordinate
 o gaussian4
 public static double gaussian4(int N,
                                Mapping func,
                                double a,
                                double b)
Numerical integration using the Gaussian integration formula (4 points).

Parameters:
N - the number of strips to use
func - a function
a - the first ordinate
b - the last ordinate
 o gaussian8
 public static double gaussian8(int N,
                                Mapping func,
                                double a,
                                double b)
Numerical integration using the Gaussian integration formula (8 points).

Parameters:
N - the number of strips to use
func - a function
a - the first ordinate
b - the last ordinate
 o differentiate
 public static double[] differentiate(int N,
                                      Mapping func,
                                      double a,
                                      double b)
Numerical differentiation.

Parameters:
N - the number of points to use
func - a function
a - the first ordinate
b - the last ordinate
 o differentiate
 public static double[][] differentiate(NMapping func,
                                        double x[],
                                        double dx[])
Numerical differentiation in multiple dimensions.

Parameters:
func - a function
x - coordinates at which to differentiate about
dx - step size
Returns:
an array Mij=dfi/dxj
 o metropolis
 public static double[] metropolis(double list[],
                                   Mapping func,
                                   double dx)
The Metropolis algorithm.

Parameters:
list - an array to be filled with values distributed according to func, set list[0] to initial value
func - distribution function
dx - step size
Returns:
list

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