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1   /*
2    * Licensed to the Hipparchus project under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The Hipparchus project licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      https://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.hipparchus.filtering.kalman.unscented;
18  
19  import org.hipparchus.filtering.kalman.Measurement;
20  import org.hipparchus.linear.RealMatrix;
21  import org.hipparchus.linear.RealVector;
22  
23  /**
24   * Unscented process that can be estimated by a {@link UnscentedKalmanFilter}.
25   * <p>
26   * This interface must be implemented by users to represent the behavior
27   * of the process to be estimated
28   * </p>
29   * @param <T> the type of the measurements
30   * @see UnscentedKalmanFilter
31   * @see org.hipparchus.filtering.kalman.unscented.UnscentedProcess
32   * @since 2.2
33   */
34  public interface UnscentedProcess<T extends Measurement>  {
35  
36      /** Get the state evolution between two times.
37       * @param previousTime time of the previous state
38       * @param sigmaPoints sigma points
39       * @param measurement measurement to process
40       * @return states evolution
41       */
42      UnscentedEvolution getEvolution(double previousTime, RealVector[] sigmaPoints, T measurement);
43  
44      /** Get the state evolution between two times.
45       * @param predictedSigmaPoints predicted state sigma points
46       * @param measurement measurement to process
47       * @return predicted measurement sigma points
48       */
49      RealVector[] getPredictedMeasurements(RealVector[] predictedSigmaPoints, T measurement);
50  
51      /** Get the innovation brought by a measurement.
52       * @param measurement measurement to process
53       * @param predictedMeasurement predicted measurement
54       * @param predictedState predicted state
55       * @param innovationCovarianceMatrix innovation covariance matrix
56       * @return innovation brought by a measurement, may be null if measurement should be rejected
57       */
58      RealVector getInnovation(T measurement, RealVector predictedMeasurement, RealVector predictedState, RealMatrix innovationCovarianceMatrix);
59  
60  }