org.apache.commons.math3.ode.events

## Class FieldEventState<T extends RealFieldElement<T>>

- java.lang.Object
- - org.apache.commons.math3.ode.events.FieldEventState<T>

- Type Parameters:
    `T` - the type of the field elements

      public class FieldEventState<T extends RealFieldElement<T>>
      extends Object

  This class handles the state for one `event handler` during integration steps.

  Each time the integrator proposes a step, the event handler switching function should be checked. This class handles the state of one handler during one integration step, with references to the state at the end of the preceding step. This information is used to decide if the handler should trigger an event or not during the proposed step.

  Since:
    3.6

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `FieldEventState(FieldEventHandler<T> handler, double maxCheckInterval, T convergence, int maxIterationCount, BracketedRealFieldUnivariateSolver<T> solver)` Simple constructor.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `evaluateStep(FieldStepInterpolator<T> interpolator)` Evaluate the impact of the proposed step on the event handler.
    `T` | `getConvergence()` Get the convergence threshold for event localization.
    `FieldEventHandler<T>` | `getEventHandler()` Get the underlying event handler.
    `T` | `getEventTime()` Get the occurrence time of the event triggered in the current step.
    `double` | `getMaxCheckInterval()` Get the maximal time interval between events handler checks.
    `int` | `getMaxIterationCount()` Get the upper limit in the iteration count for event localization.
    `void` | `reinitializeBegin(FieldStepInterpolator<T> interpolator)` Reinitialize the beginning of the step.
    `FieldODEState<T>` | `reset(FieldODEStateAndDerivative<T> state)` Let the event handler reset the state if it wants.
    `void` | `stepAccepted(FieldODEStateAndDerivative<T> state)` Acknowledge the fact the step has been accepted by the integrator.
    `boolean` | `stop()` Check if the integration should be stopped at the end of the current step.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### FieldEventState

          public FieldEventState(FieldEventHandler<T> handler,
                         double maxCheckInterval,
                         T convergence,
                         int maxIterationCount,
                         BracketedRealFieldUnivariateSolver<T> solver)

      Simple constructor.
      Parameters:
        `handler` - event handler
        `maxCheckInterval` - maximal time interval between switching function checks (this interval prevents missing sign changes in case the integration steps becomes very large)
        `convergence` - convergence threshold in the event time search
        `maxIterationCount` - upper limit of the iteration count in the event time search
        `solver` - Root-finding algorithm to use to detect state events

  - ### Method Detail

    - #### getEventHandler

          public FieldEventHandler<T> getEventHandler()

      Get the underlying event handler.
      Returns:
        underlying event handler

    - #### getMaxCheckInterval

          public double getMaxCheckInterval()

      Get the maximal time interval between events handler checks.
      Returns:
        maximal time interval between events handler checks

    - #### getConvergence

          public T getConvergence()

      Get the convergence threshold for event localization.
      Returns:
        convergence threshold for event localization

    - #### getMaxIterationCount

          public int getMaxIterationCount()

      Get the upper limit in the iteration count for event localization.
      Returns:
        upper limit in the iteration count for event localization

    - #### reinitializeBegin

          public void reinitializeBegin(FieldStepInterpolator<T> interpolator)
                                 throws MaxCountExceededException

      Reinitialize the beginning of the step.
      Parameters:
        `interpolator` - valid for the current step
      Throws:
        `MaxCountExceededException` - if the interpolator throws one because the number of functions evaluations is exceeded

    - #### evaluateStep

          public boolean evaluateStep(FieldStepInterpolator<T> interpolator)
                               throws MaxCountExceededException,
                                      NoBracketingException

      Evaluate the impact of the proposed step on the event handler.
      Parameters:
        `interpolator` - step interpolator for the proposed step
      Returns:
        true if the event handler triggers an event before the end of the proposed step
      Throws:
        `MaxCountExceededException` - if the interpolator throws one because the number of functions evaluations is exceeded
        `NoBracketingException` - if the event cannot be bracketed

    - #### getEventTime

          public T getEventTime()

      Get the occurrence time of the event triggered in the current step.
      Returns:
        occurrence time of the event triggered in the current step or infinity if no events are triggered

    - #### stepAccepted

          public void stepAccepted(FieldODEStateAndDerivative<T> state)

      Acknowledge the fact the step has been accepted by the integrator.
      Parameters:
        `state` - state at the end of the step

    - #### stop

          public boolean stop()

      Check if the integration should be stopped at the end of the current step.
      Returns:
        true if the integration should be stopped

    - #### reset

          public FieldODEState<T> reset(FieldODEStateAndDerivative<T> state)

      Let the event handler reset the state if it wants.
      Parameters:
        `state` - state at the beginning of the next step
      Returns:
        reset state (may by the same as initial state if only derivatives should be reset), or null if nothing is reset

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