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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math.ode.jacobians;
import org.apache.commons.math.ode.DerivativeException;
/**
* This interface represents a handler that should be called after
* each successful step.
*
* <p>The ODE integrators compute the evolution of the state vector at
* some grid points that depend on their own internal algorithm. Once
* they have found a new grid point (possibly after having computed
* several evaluation of the derivative at intermediate points), they
* provide it to objects implementing this interface. These objects
* typically either ignore the intermediate steps and wait for the
* last one, store the points in an ephemeris, or forward them to
* specialized processing or output methods.</p>
*
* <p>Note that is is possible to register a {@link
* org.apache.commons.math.ode.sampling.StepHandler classical step handler}
* in the low level integrator used to build a {@link FirstOrderIntegratorWithJacobians}
* rather than implementing this class. The step handlers registered at low level
* will see the big compound state whether the step handlers defined by this interface
* see the original state, and its jacobians in separate arrays.</p>
*
* <p>The compound state is guaranteed to contain the original state in the first
* elements, followed by the jacobian with respect to initial state (in row order),
* followed by the jacobian with respect to parameters (in row order). If for example
* the original state dimension is 6 and there are 3 parameters, the compound state will
* be a 60 elements array. The first 6 elements will be the original state, the next 36
* elements will be the jacobian with respect to initial state, and the remaining 18 elements
* will be the jacobian with respect to parameters.</p>
*
* <p>Dealing with low level step handlers is cumbersome if one really needs the jacobians
* in these methods, but it also prevents many data being copied back and forth between
* state and jacobians on one side and compound state on the other side. So for performance
* reasons, it is recommended to use this interface <em>only</em> if jacobians are really
* needed and to use lower level handlers if only state is needed.</p>
*
* @see FirstOrderIntegratorWithJacobians
* @see StepInterpolatorWithJacobians
* @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 févr. 2011) $
* @since 2.1
* @deprecated as of 2.2 the complete package is deprecated, it will be replaced
* in 3.0 by a completely rewritten implementation
*/
@Deprecated
public interface StepHandlerWithJacobians {
/** Determines whether this handler needs dense output.
* <p>This method allows the integrator to avoid performing extra
* computation if the handler does not need dense output.</p>
* @return true if the handler needs dense output
*/
boolean requiresDenseOutput();
/** Reset the step handler.
* Initialize the internal data as required before the first step is
* handled.
*/
void reset();
/**
* Handle the last accepted step
* @param interpolator interpolator for the last accepted step. For
* efficiency purposes, the various integrators reuse the same
* object on each call, so if the instance wants to keep it across
* all calls (for example to provide at the end of the integration a
* continuous model valid throughout the integration range, as the
* {@link org.apache.commons.math.ode.ContinuousOutputModel
* ContinuousOutputModel} class does), it should build a local copy
* using the clone method of the interpolator and store this copy.
* Keeping only a reference to the interpolator and reusing it will
* result in unpredictable behavior (potentially crashing the application).
* @param isLast true if the step is the last one
* @throws DerivativeException this exception is propagated to the
* caller if the underlying user function triggers one
*/
void handleStep(StepInterpolatorWithJacobians interpolator, boolean isLast) throws DerivativeException;
}
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