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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.commons.math.ode.sampling;
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import org.apache.commons.math.ode.ContinuousOutputModel;
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import org.apache.commons.math.ode.DerivativeException;
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import org.apache.commons.math.ode.FirstOrderIntegrator;
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import org.apache.commons.math.ode.SecondOrderIntegrator;
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* This interface represents a handler that should be called after
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* each successful step.
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* <p>The ODE integrators compute the evolution of the state vector at
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* some grid points that depend on their own internal algorithm. Once
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* they have found a new grid point (possibly after having computed
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* several evaluation of the derivative at intermediate points), they
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* provide it to objects implementing this interface. These objects
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* typically either ignore the intermediate steps and wait for the
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* last one, store the points in an ephemeris, or forward them to
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* specialized processing or output methods.</p>
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* @see FirstOrderIntegrator
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* @see SecondOrderIntegrator
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* @see StepInterpolator
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* @version $Revision: 786881 $ $Date: 2009-06-20 14:53:08 -0400 (Sat, 20 Jun 2009) $
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public interface StepHandler {
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/** Determines whether this handler needs dense output.
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* <p>This method allows the integrator to avoid performing extra
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* computation if the handler does not need dense output. If this
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* method returns false, the integrator will call the {@link
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* #handleStep} method with a {@link DummyStepInterpolator} rather
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* than a custom interpolator.</p>
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* @return true if the handler needs dense output
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public boolean requiresDenseOutput();
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/** Reset the step handler.
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* Initialize the internal data as required before the first step is
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* Handle the last accepted step
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* @param interpolator interpolator for the last accepted step. For
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* efficiency purposes, the various integrators reuse the same
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* object on each call, so if the instance wants to keep it across
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* all calls (for example to provide at the end of the integration a
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* continuous model valid throughout the integration range, as the
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* {@link ContinuousOutputModel ContinuousOutputModel} class does),
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* it should build a local copy using the clone method of the
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* interpolator and store this copy. Keeping only a reference to the
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* interpolator and reusing it will result in unpredictable
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* behaviour (potentially crashing the application).
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* @param isLast true if the step is the last one
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* @throws DerivativeException this exception is propagated to the
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* caller if the underlying user function triggers one
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public void handleStep(StepInterpolator interpolator, boolean isLast)
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throws DerivativeException;