Package org.hipparchus.ode.nonstiff

Interface FieldExplicitRungeKuttaIntegrator<T extends CalculusFieldElement<T>>

Type Parameters:
T - the type of the field elements
All Superinterfaces:
FieldButcherArrayProvider<T>, FieldODEIntegrator<T>
All Known Implementing Classes:
ClassicalRungeKuttaFieldIntegrator, DormandPrince54FieldIntegrator, DormandPrince853FieldIntegrator, EmbeddedRungeKuttaFieldIntegrator, EulerFieldIntegrator, FixedStepRungeKuttaFieldIntegrator, GillFieldIntegrator, HighamHall54FieldIntegrator, LutherFieldIntegrator, MidpointFieldIntegrator, ThreeEighthesFieldIntegrator
public interface FieldExplicitRungeKuttaIntegrator<T extends CalculusFieldElement<T>> extends FieldButcherArrayProvider<T>, FieldODEIntegrator<T>
This interface implements the part of Runge-Kutta Field integrators for Ordinary Differential Equations common to fixed- and adaptive steps.

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:
3.1
See Also:

  • Method Details

    • getRealC

      default double[] getRealC()
      Get the time steps from Butcher array (without the first zero). Real version (non-Field).
      Returns:
      time steps from Butcher array (without the first zero).

    • getRealA

      default double[][] getRealA()
      Get the internal weights from Butcher array (without the first empty row). Real version (non-Field).
      Returns:
      internal weights from Butcher array (without the first empty row)

    • getRealB

      default double[] getRealB()
      Get the external weights for the high order method from Butcher array. Real version (non-Field).
      Returns:
      external weights for the high order method from Butcher array

    • isUsingFieldCoefficients

      boolean isUsingFieldCoefficients()
      Getter for the flag between real or Field coefficients in the Butcher array.
      Returns:
      flag

    • getNumberOfStages

      default int getNumberOfStages()
      Getter for the number of stages corresponding to the Butcher array.
      Returns:
      number of stages

    • singleStep

      default T[] singleStep(FieldOrdinaryDifferentialEquation<T> equations, T t0, T[] y0, T t)
      Fast computation of a single step of ODE integration.

      This method is intended for the limited use case of very fast computation of only one step without using any of the rich features of general integrators that may take some time to set up (i.e. no step handlers, no events handlers, no additional states, no interpolators, no error control, no evaluations count, no sanity checks ...). It handles the strict minimum of computation, so it can be embedded in outer loops.

      This method is not used at all by the FieldODEIntegrator.integrate(FieldExpandableODE, org.hipparchus.ode.FieldODEState, CalculusFieldElement) method. It also completely ignores the step set at construction time, and uses only a single step to go from t0 to t.

      As this method does not use any of the state-dependent features of the integrator, it should be reasonably thread-safe if and only if the provided differential equations are themselves thread-safe.

      Parameters:
      equations - differential equations to integrate
      t0 - initial time
      y0 - initial value of the state vector at t0
      t - target time for the integration (can be set to a value smaller than t0 for backward integration)
      Returns:
      state vector at t

    • fraction

      static <T extends CalculusFieldElement<T>> T fraction(Field<T> field, int p, int q)
      Create a fraction from integers.
      Type Parameters:
      T - the type of the field elements
      Parameters:
      field - field to which elements belong
      p - numerator
      q - denominator
      Returns:
      p/q computed in the instance field

    • fraction

      static <T extends CalculusFieldElement<T>> T fraction(Field<T> field, double p, double q)
      Create a fraction from doubles.
      Type Parameters:
      T - the type of the field elements
      Parameters:
      field - field to which elements belong
      p - numerator
      q - denominator
      Returns:
      p/q computed in the instance field

    • applyInternalButcherWeights

      static <T extends CalculusFieldElement<T>> void applyInternalButcherWeights(FieldExpandableODE<T> equations, T t0, T[] y0, T h, T[][] a, T[] c, T[][] yDotK)
      Apply internal weights of Butcher array, with corresponding times.
      Type Parameters:
      T - the type of the field elements
      Parameters:
      equations - differential equations to integrate
      t0 - initial time
      y0 - initial value of the state vector at t0
      h - step size
      a - internal weights of Butcher array
      c - times of Butcher array
      yDotK - array where to store result

    • applyInternalButcherWeights

      static <T extends CalculusFieldElement<T>> void applyInternalButcherWeights(FieldExpandableODE<T> equations, T t0, T[] y0, T h, double[][] a, double[] c, T[][] yDotK)
      Apply internal weights of Butcher array, with corresponding times. Version with real Butcher array (non-Field).
      Type Parameters:
      T - the type of the field elements
      Parameters:
      equations - differential equations to integrate
      t0 - initial time
      y0 - initial value of the state vector at t0
      h - step size
      a - internal weights of Butcher array
      c - times of Butcher array
      yDotK - array where to store result

    • applyExternalButcherWeights

      static <T extends CalculusFieldElement<T>> T[] applyExternalButcherWeights(T[] y0, T[][] yDotK, T h, T[] b)
      Apply external weights of Butcher array, assuming internal ones have been applied.
      Type Parameters:
      T - the type of the field elements
      Parameters:
      y0 - initial value of the state vector at t0
      yDotK - output of stages
      h - step size
      b - external weights of Butcher array
      Returns:
      state vector

    • applyExternalButcherWeights

      static <T extends CalculusFieldElement<T>> T[] applyExternalButcherWeights(T[] y0, T[][] yDotK, T h, double[] b)
      Apply external weights of Butcher array, assuming internal ones have been applied. Version with real Butcher array (non-Field version).
      Type Parameters:
      T - the type of the field elements
      Parameters:
      y0 - initial value of the state vector at t0
      yDotK - output of stages
      h - step size
      b - external weights of Butcher array
      Returns:
      state vector