AbstractMatricesHarvester.java
- /* Copyright 2002-2024 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS 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.orekit.propagation;
- import java.util.List;
- import org.hipparchus.linear.MatrixUtils;
- import org.hipparchus.linear.RealMatrix;
- import org.orekit.orbits.PositionAngleType;
- import org.orekit.utils.DoubleArrayDictionary;
- /** Base harvester between two-dimensional Jacobian matrices and one-dimensional {@link
- * SpacecraftState#getAdditionalState(String) additional state arrays}.
- * @author Luc Maisonobe
- * @since 11.1
- */
- public abstract class AbstractMatricesHarvester implements MatricesHarvester {
- /** State dimension, fixed to 6. */
- public static final int STATE_DIMENSION = 6;
- /** Identity conversion matrix. */
- private static final double[][] IDENTITY = {
- { 1.0, 0.0, 0.0, 0.0, 0.0, 0.0 },
- { 0.0, 1.0, 0.0, 0.0, 0.0, 0.0 },
- { 0.0, 0.0, 1.0, 0.0, 0.0, 0.0 },
- { 0.0, 0.0, 0.0, 1.0, 0.0, 0.0 },
- { 0.0, 0.0, 0.0, 0.0, 1.0, 0.0 },
- { 0.0, 0.0, 0.0, 0.0, 0.0, 1.0 }
- };
- /** Initial State Transition Matrix. */
- private final RealMatrix initialStm;
- /** Initial columns of the Jacobians matrix with respect to parameters. */
- private final DoubleArrayDictionary initialJacobianColumns;
- /** State Transition Matrix state name. */
- private final String stmName;
- /** Simple constructor.
- * <p>
- * The arguments for initial matrices <em>must</em> be compatible with the {@link org.orekit.orbits.OrbitType orbit type}
- * and {@link PositionAngleType position angle} that will be used by propagator
- * </p>
- * @param stmName State Transition Matrix state name
- * @param initialStm initial State Transition Matrix ∂Y/∂Y₀,
- * if null (which is the most frequent case), assumed to be 6x6 identity
- * @param initialJacobianColumns initial columns of the Jacobians matrix with respect to parameters,
- * if null or if some selected parameters are missing from the dictionary, the corresponding
- * initial column is assumed to be 0
- */
- protected AbstractMatricesHarvester(final String stmName, final RealMatrix initialStm, final DoubleArrayDictionary initialJacobianColumns) {
- this.stmName = stmName;
- this.initialStm = initialStm == null ? MatrixUtils.createRealIdentityMatrix(STATE_DIMENSION) : initialStm;
- this.initialJacobianColumns = initialJacobianColumns == null ? new DoubleArrayDictionary() : initialJacobianColumns;
- }
- /** Get the State Transition Matrix state name.
- * @return State Transition Matrix state name
- */
- public String getStmName() {
- return stmName;
- }
- /** Get the initial State Transition Matrix.
- * @return initial State Transition Matrix
- */
- public RealMatrix getInitialStateTransitionMatrix() {
- return initialStm;
- }
- /** Get the initial column of Jacobian matrix with respect to named parameter.
- * @param columnName name of the column
- * @return initial column of the Jacobian matrix
- */
- public double[] getInitialJacobianColumn(final String columnName) {
- final DoubleArrayDictionary.Entry entry = initialJacobianColumns.getEntry(columnName);
- return entry == null ? new double[STATE_DIMENSION] : entry.getValue();
- }
- /** Get the conversion Jacobian between state parameters and parameters used for derivatives.
- * <p>
- * The base implementation returns identity, which is suitable for DSST and TLE propagators,
- * as state parameters and parameters used for derivatives are the same.
- * </p>
- * <p>
- * For Numerical propagator, parameters used for derivatives are Cartesian
- * and they can be different from state parameters because the numerical propagator can accept different type
- * of orbits, so the method is overridden in derived classes.
- * </p>
- * @param state spacecraft state
- * @return conversion Jacobian
- */
- protected double[][] getConversionJacobian(final SpacecraftState state) {
- return IDENTITY;
- }
- /** {@inheritDoc} */
- @Override
- public void setReferenceState(final SpacecraftState reference) {
- // nothing to do
- }
- /** {@inheritDoc} */
- @Override
- public RealMatrix getStateTransitionMatrix(final SpacecraftState state) {
- if (!state.hasAdditionalState(stmName)) {
- return null;
- }
- // get the conversion Jacobian
- final double[][] dYdC = getConversionJacobian(state);
- // extract the additional state
- final double[] p = state.getAdditionalState(stmName);
- // compute dYdY0 = dYdC * dCdY0
- final RealMatrix dYdY0 = MatrixUtils.createRealMatrix(STATE_DIMENSION, STATE_DIMENSION);
- for (int i = 0; i < STATE_DIMENSION; i++) {
- final double[] rowC = dYdC[i];
- for (int j = 0; j < STATE_DIMENSION; ++j) {
- double sum = 0;
- int pIndex = j;
- for (int k = 0; k < STATE_DIMENSION; ++k) {
- sum += rowC[k] * p[pIndex];
- pIndex += STATE_DIMENSION;
- }
- dYdY0.setEntry(i, j, sum);
- }
- }
- return dYdY0;
- }
- /** {@inheritDoc} */
- @Override
- public RealMatrix getParametersJacobian(final SpacecraftState state) {
- final List<String> columnsNames = getJacobiansColumnsNames();
- if (columnsNames == null || columnsNames.isEmpty()) {
- return null;
- }
- // get the conversion Jacobian
- final double[][] dYdC = getConversionJacobian(state);
- // compute dYdP = dYdC * dCdP
- final RealMatrix dYdP = MatrixUtils.createRealMatrix(STATE_DIMENSION, columnsNames.size());
- for (int j = 0; j < columnsNames.size(); j++) {
- final double[] p = state.getAdditionalState(columnsNames.get(j));
- for (int i = 0; i < STATE_DIMENSION; ++i) {
- final double[] dYdCi = dYdC[i];
- double sum = 0;
- for (int k = 0; k < STATE_DIMENSION; ++k) {
- sum += dYdCi[k] * p[k];
- }
- dYdP.setEntry(i, j, sum);
- }
- }
- return dYdP;
- }
- /** Freeze the names of the Jacobian columns.
- * <p>
- * This method is called when propagation starts, i.e. when configuration is completed
- * </p>
- */
- public abstract void freezeColumnsNames();
- }