| /* |
| * 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.sampling; |
| |
| import java.io.Externalizable; |
| |
| import org.apache.commons.math.ode.DerivativeException; |
| |
| /** This interface represents an interpolator over the last step |
| * during an ODE integration. |
| * |
| * <p>The various ODE integrators provide objects implementing this |
| * interface to the step handlers. These objects are often custom |
| * objects tightly bound to the integrator internal algorithms. The |
| * handlers can use these objects to retrieve the state vector at |
| * intermediate times between the previous and the current grid points |
| * (this feature is often called dense output).</p> |
| * <p>One important thing to note is that the step handlers may be so |
| * tightly bound to the integrators that they often share some internal |
| * state arrays. This imply that one should <em>never</em> use a direct |
| * reference to a step interpolator outside of the step handler, either |
| * for future use or for use in another thread. If such a need arise, the |
| * step interpolator <em>must</em> be copied using the dedicated |
| * {@link #copy()} method. |
| * </p> |
| * |
| * @see org.apache.commons.math.ode.FirstOrderIntegrator |
| * @see org.apache.commons.math.ode.SecondOrderIntegrator |
| * @see StepHandler |
| * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 févr. 2011) $ |
| * @since 1.2 |
| */ |
| |
| public interface StepInterpolator extends Externalizable { |
| |
| /** |
| * Get the previous grid point time. |
| * @return previous grid point time |
| */ |
| double getPreviousTime(); |
| |
| /** |
| * Get the current grid point time. |
| * @return current grid point time |
| */ |
| double getCurrentTime(); |
| |
| /** |
| * Get the time of the interpolated point. |
| * If {@link #setInterpolatedTime} has not been called, it returns |
| * the current grid point time. |
| * @return interpolation point time |
| */ |
| double getInterpolatedTime(); |
| |
| /** |
| * Set the time of the interpolated point. |
| * <p>Setting the time outside of the current step is now allowed, but |
| * should be used with care since the accuracy of the interpolator will |
| * probably be very poor far from this step. This allowance has been |
| * added to simplify implementation of search algorithms near the |
| * step endpoints.</p> |
| * <p>Setting the time changes the instance internal state. If a |
| * specific state must be preserved, a copy of the instance must be |
| * created using {@link #copy()}.</p> |
| * @param time time of the interpolated point |
| */ |
| void setInterpolatedTime(double time); |
| |
| /** |
| * Get the state vector of the interpolated point. |
| * <p>The returned vector is a reference to a reused array, so |
| * it should not be modified and it should be copied if it needs |
| * to be preserved across several calls.</p> |
| * @return state vector at time {@link #getInterpolatedTime} |
| * @see #getInterpolatedDerivatives() |
| * @exception DerivativeException if user code called from step interpolator |
| * finalization triggers one |
| */ |
| double[] getInterpolatedState() throws DerivativeException; |
| |
| /** |
| * Get the derivatives of the state vector of the interpolated point. |
| * <p>The returned vector is a reference to a reused array, so |
| * it should not be modified and it should be copied if it needs |
| * to be preserved across several calls.</p> |
| * @return derivatives of the state vector at time {@link #getInterpolatedTime} |
| * @see #getInterpolatedState() |
| * @exception DerivativeException if user code called from step interpolator |
| * finalization triggers one |
| * @since 2.0 |
| */ |
| double[] getInterpolatedDerivatives() throws DerivativeException; |
| |
| /** Check if the natural integration direction is forward. |
| * <p>This method provides the integration direction as specified by |
| * the integrator itself, it avoid some nasty problems in |
| * degenerated cases like null steps due to cancellation at step |
| * initialization, step control or discrete events |
| * triggering.</p> |
| * @return true if the integration variable (time) increases during |
| * integration |
| */ |
| boolean isForward(); |
| |
| /** Copy the instance. |
| * <p>The copied instance is guaranteed to be independent from the |
| * original one. Both can be used with different settings for |
| * interpolated time without any side effect.</p> |
| * @return a deep copy of the instance, which can be used independently. |
| * @exception DerivativeException if user code called from step interpolator |
| * finalization triggers one |
| * @see #setInterpolatedTime(double) |
| */ |
| StepInterpolator copy() throws DerivativeException; |
| |
| } |