/* 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.files.ccsds.ndm.cdm;
  
  import org.hipparchus.linear.MatrixUtils;
  import org.hipparchus.linear.RealMatrix;
  import org.orekit.files.ccsds.section.CommentsContainer;
  
  /**
   * Container for RTN covariance matrix data. This class as a RealMatrix as
   * attribute which can be acces with getRTNCovariaxMatrix method. Beware that
   * there are thus 2 ways to modify the RTN covariance : setC... ( setCrr,
   * setCtr ...) which should be prioritized and getRTNCovariaxMatrix.setEntry(row, col, value).
   * <p> The RTN Covariance Matrix is provided in the 9×9 Lower Triangular Form. All parameters of the 6×6 position/velocity submatrix
   * are mandatory. The remaining elements will return NaN if not provided. </p>
   * @author Melina Vanel
   * @since 11.2
   */
  public class RTNCovariance extends CommentsContainer {
  
      /** RTN covariance matrix. */
      private RealMatrix covarianceMatrix;
  
      /** Simple constructor. To update matrix value there are 2 ways to modify the RTN
       * covariance : setC... ( setCrr, setCtr ...) which should be prioritized and
       * getRTNCovariaxMatrix.setEntry(row, col, value).
       * <p> The RTN Covariance Matrix is provided in the 9×9 Lower Triangular Form. All parameters of the 6×6 position/velocity submatrix
       * are mandatory. The remaining elements will return NaN if not provided. </p>
       */
      public RTNCovariance() {
          covarianceMatrix = MatrixUtils.createRealMatrix(9, 9);
          for (int i = 0; i < covarianceMatrix.getRowDimension(); ++i) {
              for (int j = 0; j <= i; ++j) {
                  covarianceMatrix.setEntry(i, j, Double.NaN);
              }
          }
  
      }
  
      /** {@inheritDoc} */
      @Override
      public void validate(final double version) {
          super.validate(version);
          // We only check values that are mandatory in a cdm file
          checkNotNaN(getCrr(),              RTNCovarianceKey.CR_R.name());
          checkNotNaN(getCtr(),              RTNCovarianceKey.CT_R.name());
          checkNotNaN(getCtt(),              RTNCovarianceKey.CT_T.name());
          checkNotNaN(getCnr(),              RTNCovarianceKey.CN_R.name());
          checkNotNaN(getCnt(),              RTNCovarianceKey.CN_T.name());
          checkNotNaN(getCnn(),              RTNCovarianceKey.CN_N.name());
          checkNotNaN(getCrdotr(),           RTNCovarianceKey.CRDOT_R.name());
          checkNotNaN(getCrdott(),           RTNCovarianceKey.CRDOT_T.name());
          checkNotNaN(getCrdotn(),           RTNCovarianceKey.CRDOT_N.name());
          checkNotNaN(getCrdotrdot(),        RTNCovarianceKey.CRDOT_RDOT.name());
          checkNotNaN(getCtdotr(),           RTNCovarianceKey.CTDOT_R.name());
          checkNotNaN(getCtdott(),           RTNCovarianceKey.CTDOT_T.name());
          checkNotNaN(getCtdotn(),           RTNCovarianceKey.CTDOT_N.name());
          checkNotNaN(getCtdotrdot(),        RTNCovarianceKey.CTDOT_RDOT.name());
          checkNotNaN(getCtdottdot(),        RTNCovarianceKey.CTDOT_TDOT.name());
          checkNotNaN(getCndotr(),           RTNCovarianceKey.CNDOT_R.name());
          checkNotNaN(getCndott(),           RTNCovarianceKey.CNDOT_T.name());
          checkNotNaN(getCndotn(),           RTNCovarianceKey.CNDOT_N.name());
          checkNotNaN(getCndotrdot(),        RTNCovarianceKey.CNDOT_RDOT.name());
          checkNotNaN(getCndottdot(),        RTNCovarianceKey.CNDOT_TDOT.name());
          checkNotNaN(getCndotndot(),        RTNCovarianceKey.CNDOT_NDOT.name());
      }
  
      /** Set an entry in the RTN covariance matrix.
       * <p>
       * Both m(j, k) and m(k, j) are set.
       * </p>
       * @param j row index (must be between 0 and 5 (inclusive)
       * @param k column index (must be between 0 and 5 (inclusive)
       * @param entry value of the matrix entry
       */
      public void setCovarianceMatrixEntry(final int j, final int k, final double entry) {
          covarianceMatrix.setEntry(j, k, entry);
          covarianceMatrix.setEntry(k, j, entry);
      }
  
      /**
       * Get the RTN covariance matrix.
       * <p> The RTN Covariance Matrix is provided in the 9×9 Lower Triangular Form. All parameters of the 6×6 position/velocity submatrix
       * are mandatory. The remaining elements will return NaN if not provided. </p>
       * @return the RTN covariance matrix
      */
     public RealMatrix getRTNCovarianceMatrix() {
         return covarianceMatrix;
     }
 
     /**
      * Get the object [1,1] in covariance matrix (with index starting at 1).
      * @return the object [1,1] in covariance matrix (in m²)
      */
     public double getCrr() {
         return covarianceMatrix.getEntry(0, 0);
     }
 
     /**
      * Set the object [1,1] in covariance matrix (with index starting at 1).
      * @param CRR = object [1,1] in covariance matrix (in m²)
      */
     public void setCrr(final double CRR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(0, 0, CRR);
     }
 
     /**
      * Get the object [2,1] in covariance matrix (with index starting at 1).
      * @return the object [2,1] in covariance matrix (in m²)
      */
     public double getCtr() {
         return covarianceMatrix.getEntry(1, 0);
     }
 
     /**
      * Set the object [2,1] in covariance matrix (with index starting at 1).
      * @param CTR = object [2,1] in covariance matrix (in m²)
      */
     public void setCtr(final double CTR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(1, 0, CTR);
     }
 
     /**
      * Get the object [2,2] in covariance matrix (with index starting at 1).
      * @return the object [2,2] in covariance matrix (in m²)
      */
     public double getCtt() {
         return covarianceMatrix.getEntry(1, 1);
     }
 
     /**
      * Set the object [2,2] in covariance matrix (with index starting at 1).
      * @param CTT = object [2,2] in covariance matrix (in m²)
      */
     public void setCtt(final double CTT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(1, 1, CTT);
     }
 
     /**
      * Get the object [3,1] in covariance matrix (with index starting at 1).
      * @return the object [3,1] in covariance matrix (in m²)
      */
     public double getCnr() {
         return covarianceMatrix.getEntry(2, 0);
     }
 
     /**
      * Set the object [3,1] in covariance matrix (with index starting at 1).
      * @param CNR = object [3,1] in covariance matrix (in m²)
      */
     public void setCnr(final double CNR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(2, 0, CNR);
     }
 
     /**
      * Get the object [3,2] in covariance matrix (with index starting at 1).
      * @return the object [3,2] in covariance matrix (in m²)
      */
     public double getCnt() {
         return covarianceMatrix.getEntry(2, 1);
     }
 
     /**
      * Set the object [3,2] in covariance matrix (with index starting at 1).
      * @param CNT = object [3,2] in covariance matrix (in m²)
      */
     public void setCnt(final double CNT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(2, 1, CNT);
     }
 
     /**
      * Get the object [3,3] in covariance matrix (with index starting at 1).
      * @return the object [3,3] in covariance matrix (in m²)
      */
     public double getCnn() {
         return covarianceMatrix.getEntry(2, 2);
     }
 
     /**
      * Set the object [3,3] in covariance matrix (with index starting at 1).
      * @param CNN = object [3,3] in covariance matrix (in m²)
      */
     public void setCnn(final double CNN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(2, 2, CNN);
     }
 
     /**
      * Get the object [4,1] in covariance matrix (with index starting at 1).
      * @return the object [4,1] in covariance matrix (in m²/s)
      */
     public double getCrdotr() {
         return covarianceMatrix.getEntry(3, 0);
     }
 
     /**
      * Set the object [4,1] in covariance matrix (with index starting at 1).
      * @param CRdotR = object [4,1] in covariance matrix (in m²/s)
      */
     public void setCrdotr(final double CRdotR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(3, 0, CRdotR);
     }
 
     /**
      * Get the object [4,2] in covariance matrix (with index starting at 1).
      * @return the object [4,2] in covariance matrix (in m²/s)
      */
     public double getCrdott() {
         return covarianceMatrix.getEntry(3, 1);
     }
 
     /**
      * Set the object [4, 2] in covariance matrix (with index starting at 1).
      * @param CRdotT = object [4, 2] in covariance matrix (in m²/s)
      */
     public void setCrdott(final double CRdotT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(3, 1, CRdotT);
     }
 
     /**
      * Get the object [4, 3] in covariance matrix (with index starting at 1) .
      * @return the object [4, 3] in covariance matrix (in m²/s)
      */
     public double getCrdotn() {
         return covarianceMatrix.getEntry(3, 2);
     }
 
     /**
      * Set the object [4, 3] in covariance matrix (with index starting at 1).
      * @param CRdotN = object [4,3] in covariance matrix (in m²/s)
      */
     public void setCrdotn(final double CRdotN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(3, 2, CRdotN);
     }
 
     /**
      * Get the object [4, 4] in covariance matrix (with index starting at 1).
      * @return the object [4, 4] in covariance matrix (in m²/s²)
      */
     public double getCrdotrdot() {
         return covarianceMatrix.getEntry(3, 3);
     }
 
     /**
      * Set the object [4, 4] in covariance matrix (with index starting at 1).
      * @param CRdotRdot = object [4, 4] in covariance matrix (in m²/s²)
      */
     public void setCrdotrdot(final double CRdotRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(3, 3, CRdotRdot);
     }
 
     /**
      * Get the object [5, 1] in covariance matrix (with index starting at 1).
      * @return the object [5, 1] in covariance matrix (in m²/s)
      */
     public double getCtdotr() {
         return covarianceMatrix.getEntry(4, 0);
     }
 
     /**
      * Set the object [5,1] in covariance matrix (with index starting at 1).
      * @param CTdotR = object [5,1] in covariance matrix (in m²/s)
      */
     public void setCtdotr(final double CTdotR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(4, 0, CTdotR);
     }
 
     /**
      * Get the object [5,2] in covariance matrix (with index starting at 1).
      * @return the object [5,2] in covariance matrix (in m²/s)
      */
     public double getCtdott() {
         return covarianceMatrix.getEntry(4, 1);
     }
 
     /**
      * Set the object [5,2] in covariance matrix (with index starting at 1).
      * @param CTdotT = object [5,2] in covariance matrix (in m²/s)
      */
     public void setCtdott(final double CTdotT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(4, 1, CTdotT);
     }
 
     /**
      * Get the object [5,3] in covariance matrix (with index starting at 1).
      * @return the object [5,3] in covariance matrix (in m²/s)
      */
     public double getCtdotn() {
         return covarianceMatrix.getEntry(4, 2);
     }
 
     /**
      * Set the object [5,3] in covariance matrix (with index starting at 1).
      * @param CTdotN = object [5,3] in covariance matrix (in m²/s)
      */
     public void setCtdotn(final double CTdotN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(4, 2, CTdotN);
     }
 
     /**
      * Get the object [5,4] in covariance matrix (with index starting at 1).
      * @return the object [5,4] in covariance matrix (in m²/s²)
      */
     public double getCtdotrdot() {
         return covarianceMatrix.getEntry(4, 3);
     }
 
     /**
      * Set the object [5,4] in covariance matrix (with index starting at 1).
      * @param CTdotRdot = object [5,4] in covariance matrix (in m²/s²)
      */
     public void setCtdotrdot(final double CTdotRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(4, 3, CTdotRdot);
     }
 
     /**
      * Get the object [5,5] in covariance matrix (with index starting at 1).
      * @return the object [5,5] in covariance matrix (in m²/s²)
      */
     public double getCtdottdot() {
         return covarianceMatrix.getEntry(4, 4);
     }
 
     /**
      * Set the object [5,5] in covariance matrix (with index starting at 1).
      * @param CTdotTdot = object [5,5] in covariance matrix (in m²/s²)
      */
     public void setCtdottdot(final double CTdotTdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(4, 4, CTdotTdot);
     }
 
     /**
      * Get the object [6,1] in covariance matrix (with index starting at 1).
      * @return the object [6,1] in covariance matrix (in m²/s)
      */
     public double getCndotr() {
         return covarianceMatrix.getEntry(5, 0);
     }
 
     /**
      * Set the object [6,1] in covariance matrix (with index starting at 1).
      * @param CNdotR = object [6,1] in covariance matrix (in m²/s)
      */
     public void setCndotr(final double CNdotR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 0, CNdotR);
     }
 
     /**
      * Get the object [6,2] in covariance matrix (with index starting at 1).
      * @return the object [6,2] in covariance matrix (in m²/s)
      */
     public double getCndott() {
         return covarianceMatrix.getEntry(5, 1);
     }
 
     /**
      * Set the object [6,2] in covariance matrix (with index starting at 1).
      * @param CNdotT = object [6,2] in covariance matrix (in m²/s)
      */
     public void setCndott(final double CNdotT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 1, CNdotT);
     }
 
     /**
      * Get the object [6,3] in covariance matrix (with index starting at 1).
      * @return the object [6,3] in covariance matrix (in m²/s)
      */
     public double getCndotn() {
         return covarianceMatrix.getEntry(5, 2);
     }
 
     /**
      * Set the object [6,3] in covariance matrix (with index starting at 1).
      * @param CNdotN = object [6,3] in covariance matrix (in m²/s)
      */
     public void setCndotn(final double CNdotN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 2, CNdotN);
     }
 
     /**
      * Get the object [6,4] in covariance matrix (with index starting at 1).
      * @return the object [6,4] in covariance matrix (in m²/s²)
      */
     public double getCndotrdot() {
         return covarianceMatrix.getEntry(5, 3);
     }
 
     /**
      * Set the object [6,4] in covariance matrix (with index starting at 1).
      * @param CNdotRdot = object [6,4] in covariance matrix (in m²/s²)
      */
     public void setCndotrdot(final double CNdotRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 3, CNdotRdot);
     }
 
     /**
      * Get the object [6,5] in covariance matrix (with index starting at 1).
      * @return the object [6,5] in covariance matrix (in m²/s²)
      */
     public double getCndottdot() {
         return covarianceMatrix.getEntry(5, 4);
     }
 
     /**
      * Set the object [6,5] in covariance matrix (with index starting at 1).
      * @param CNdotTdot = object [6,5] in covariance matrix (in m²/s²)
      */
     public void setCndottdot(final double CNdotTdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 4, CNdotTdot);
     }
 
     /**
      * Get the object [6,6] in covariance matrix (with index starting at 1).
      * @return the object [6,6] in covariance matrix (in m²/s²)
      */
     public double getCndotndot() {
         return covarianceMatrix.getEntry(5, 5);
     }
 
     /**
      * Set the object [6,6] in covariance matrix (with index starting at 1).
      * @param CNdotNdot = object [6,6] in covariance matrix (in m²/s²)
      */
     public void setCndotndot(final double CNdotNdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(5, 5, CNdotNdot);
     }
 
     /**
      * Get the object [7,1] in covariance matrix (with index starting at 1).
      * @return the object [7,1] in covariance matrix (in m³/kg)
      */
     public double getCdrgr() {
         return covarianceMatrix.getEntry(6, 0);
     }
 
     /**
      * Set the object [7,1] in covariance matrix (with index starting at 1).
      * @param CDRGR = object [7,1] in covariance matrix (in m³/kg)
      */
     public void setCdrgr(final double CDRGR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 0, CDRGR);
     }
 
     /**
      * Get the object [7,2] in covariance matrix.
      * @return the object [7,2] in covariance matrix (in m³/kg)
      */
     public double getCdrgt() {
         return covarianceMatrix.getEntry(6, 1);
     }
 
     /**
      * Set the object [7,2] in covariance matrix (with index starting at 1).
      * @param CDRGT = object [7,2] in covariance matrix (in m³/kg)
      */
     public void setCdrgt(final double CDRGT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 1, CDRGT);
     }
 
     /**
      * Get the object [7,3] in covariance matrix (with index starting at 1).
      * @return the object [7,3] in covariance matrix (in m³/kg)
      */
     public double getCdrgn() {
         return covarianceMatrix.getEntry(6, 2);
     }
 
     /**
      * Set the object [7,3] in covariance matrix (with index starting at 1).
      * @param CDRGN = object [7,3] in covariance matrix (in m³/kg)
      */
     public void setCdrgn(final double CDRGN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 2, CDRGN);
     }
 
     /**
      * Get the object [7,4] in covariance matrix (with index starting at 1).
      * @return the object [7,4] in covariance matrix (in m³/(kg.s))
      */
     public double getCdrgrdot() {
         return covarianceMatrix.getEntry(6, 3);
     }
 
     /**
      * Set the object [7,4] in covariance matrix (with index starting at 1).
      * @param CDRGRdot = object [7,4] in covariance matrix (in m³/(kg.s))
      */
     public void setCdrgrdot(final double CDRGRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 3, CDRGRdot);
     }
 
     /**
      * Get the object [7,5] in covariance matrix (with index starting at 1).
      * @return the object [7,5] in covariance matrix (in m³/(kg.s))
      */
     public double getCdrgtdot() {
         return covarianceMatrix.getEntry(6, 4);
     }
 
     /**
      * Set the object [7,5] in covariance matrix (with index starting at 1).
      * @param CDRGTdot = object [7,5] in covariance matrix (in m³/(kg.s))
      */
     public void setCdrgtdot(final double CDRGTdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 4, CDRGTdot);
     }
 
     /**
      * Get the object [7,6] in covariance matrix (with index starting at 1).
      * @return the object [7,6] in covariance matrix (in m³/(kg.s))
      */
     public double getCdrgndot() {
         return covarianceMatrix.getEntry(6, 5);
     }
 
     /**
      * Set the object [7,6] in covariance matrix (with index starting at 1).
      * @param CDRGNdot = object [7,6] in covariance matrix (in m³/(kg.s))
      */
     public void setCdrgndot(final double CDRGNdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 5, CDRGNdot);
     }
 
     /**
      * Get the object [7,7] in covariance matrix (with index starting at 1).
      * @return the object [7,7] in covariance matrix (in m⁴/kg²)
      */
     public double getCdrgdrg() {
         return covarianceMatrix.getEntry(6, 6);
     }
 
     /**
      * Set the object [7,7] in covariance matrix (with index starting at 1).
      * @param CDRGDRG = object [7,7] in covariance matrix (in m⁴/kg²)
      */
     public void setCdrgdrg(final double CDRGDRG) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(6, 6, CDRGDRG);
     }
 
     /**
      * Get the object [8,1] in covariance matrix (with index starting at 1).
      * @return the object [8,1] in covariance matrix (in m³/kg)
      */
     public double getCsrpr() {
         return covarianceMatrix.getEntry(7, 0);
     }
 
     /**
      * Set the object [8,1] in covariance matrix (with index starting at 1).
      * @param CSRPR = object [8,1] in covariance matrix (in m³/kg)
      */
     public void setCsrpr(final double CSRPR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 0, CSRPR);
     }
 
     /**
      * Get the object [8,2] in covariance matrix (with index starting at 1).
      * @return the object [8,2] in covariance matrix (in m³/kg)
      */
     public double getCsrpt() {
         return covarianceMatrix.getEntry(7, 1);
     }
 
     /**
      * Set the object [8,2] in covariance matrix (with index starting at 1).
      * @param CSRPT = object [8,2] in covariance matrix (in m³/kg)
      */
     public void setCsrpt(final double CSRPT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 1, CSRPT);
     }
 
     /**
      * Get the object [8,3] in covariance matrix (with index starting at 1).
      * @return the object [8,3] in covariance matrix (in m³/kg)
      */
     public double getCsrpn() {
         return covarianceMatrix.getEntry(7, 2);
     }
 
     /**
      * Set the object [8,3] in covariance matrix (with index starting at 1).
      * @param CSRPN = object [8,3] in covariance matrix (in m³/kg)
      */
     public void setCsrpn(final double CSRPN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 2, CSRPN);
     }
 
     /**
      * Get the object [8,4] in covariance matrix (with index starting at 1).
      * @return the object [8,4] in covariance matrix (in m³/(kg.s))
      */
     public double getCsrprdot() {
         return covarianceMatrix.getEntry(7, 3);
     }
 
     /**
      * Set the object [8,4] in covariance matrix (with index starting at 1).
      * @param CSRPRdot = object [8,4] in covariance matrix (in m³/(kg.s))
      */
     public void setCsrprdot(final double CSRPRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 3, CSRPRdot);
     }
 
     /**
      * Get the object [8,5] in covariance matrix (with index starting at 1).
      * @return the object [8,5] in covariance matrix (in m³/(kg.s))
      */
     public double getCsrptdot() {
         return covarianceMatrix.getEntry(7, 4);
     }
 
     /**
      * Set the object [8,5] in covariance matrix (with index starting at 1).
      * @param CSRPTdot = object [8,5] in covariance matrix (in m³/(kg.s))
      */
     public void setCsrptdot(final double CSRPTdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 4, CSRPTdot);
     }
 
     /**
      * Get the object [8,6] in covariance matrix (with index starting at 1).
      * @return the object [8,6] in covariance matrix (in m³/(kg.s))
      */
     public double getCsrpndot() {
         return covarianceMatrix.getEntry(7, 5);
     }
 
     /**
      * Set the object [8,6] in covariance matrix (with index starting at 1).
      * @param CSRPNdot = object [8,6] in covariance matrix (in m³/(kg.s))
      */
     public void setCsrpndot(final double CSRPNdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 5, CSRPNdot);
     }
 
     /**
      * Get the object [8,7] in covariance matrix (with index starting at 1).
      * @return the object [8,7] in covariance matrix (in m⁴/kg²)
      */
     public double getCsrpdrg() {
         return covarianceMatrix.getEntry(7, 6);
     }
 
     /**
      * Set the object [8,7] in covariance matrix (with index starting at 1).
      * @param CSRPDRG = object [8,7] in covariance matrix (in m⁴/kg²)
      */
     public void setCsrpdrg(final double CSRPDRG) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 6, CSRPDRG);
     }
 
     /**
      * Get the object [8,8] in covariance matrix (with index starting at 1).
      * @return the object [8,8] in covariance matrix (in m⁴/kg²)
      */
     public double getCsrpsrp() {
         return covarianceMatrix.getEntry(7, 7);
     }
 
     /**
      * Set the object [8,8] in covariance matrix (with index starting at 1).
      * @param CSRPSRP = object [8,8] in covariance matrix (in m⁴/kg²)
      */
     public void setCsrpsrp(final double CSRPSRP) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(7, 7, CSRPSRP);
     }
 
     /**
      * Get the object [9,1] in covariance matrix (with index starting at 1).
      * @return the object [9,1] in covariance matrix (in m²/s²)
      */
     public double getCthrr() {
         return covarianceMatrix.getEntry(8, 0);
     }
 
     /**
      * Set the object [9,1] in covariance matrix (with index starting at 1).
      * @param CTHRR = object [9,1] in covariance matrix (in m²/s²)
      */
     public void setCthrr(final double CTHRR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 0, CTHRR);
     }
 
     /**
      * Get the object [9,2] in covariance matrix (with index starting at 1).
      * @return the object [9,2] in covariance matrix (in m²/s²)
      */
     public double getCthrt() {
         return covarianceMatrix.getEntry(8, 1);
     }
 
     /**
      * Set the object [9,2] in covariance matrix (with index starting at 1).
      * @param CTHRT = object [9,2] in covariance matrix (in m²/s²)
      */
     public void setCthrt(final double CTHRT) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 1, CTHRT);
     }
 
     /**
      * Get the object [9,3] in covariance matrix (with index starting at 1).
      * @return the object [9,3] in covariance matrix (in m²/s²)
      */
     public double getCthrn() {
         return covarianceMatrix.getEntry(8, 2);
     }
 
     /**
      * Set the object [9,3] in covariance matrix (with index starting at 1).
      * @param CTHRN = object [9,3] in covariance matrix (in m²/s²)
      */
     public void setCthrn(final double CTHRN) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 2, CTHRN);
     }
 
     /**
      * Get the object [9,4] in covariance matrix (with index starting at 1).
      * @return the object [9,4] in covariance matrix (in m²/s³)
      */
     public double getCthrrdot() {
         return covarianceMatrix.getEntry(8, 3);
     }
 
     /**
      * Set the object [9,4] in covariance matrix (with index starting at 1).
      * @param CTHRRdot = object [9,4] in covariance matrix (in m²/s³)
      */
     public void setCthrrdot(final double CTHRRdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 3, CTHRRdot);
     }
 
     /**
      * Get the object [9,5] in covariance matrix (with index starting at 1).
      * @return the object [9,5] in covariance matrix (in m²/s³)
      */
     public double getCthrtdot() {
         return covarianceMatrix.getEntry(8, 4);
     }
 
     /**
      * Set the object [9,5] in covariance matrix (with index starting at 1).
      * @param CTHRTdot = object [9,5] in covariance matrix (in m²/s³)
      */
     public void setCthrtdot(final double CTHRTdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 4, CTHRTdot);
     }
 
     /**
      * Get the object [9,6] in covariance matrix (with index starting at 1).
      * @return the object [9,6] in covariance matrix (in m²/s³)
      */
     public double getCthrndot() {
         return covarianceMatrix.getEntry(8, 5);
     }
 
     /**
      * Set the object [9,6] in covariance matrix (with index starting at 1).
      * @param CTHRNdot = object [9,6] in covariance matrix (in m²/s³)
      */
     public void setCthrndot(final double CTHRNdot) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 5, CTHRNdot);
     }
 
     /**
      * Get the object [9,7] in covariance matrix (with index starting at 1).
      * @return the object [9,7] in covariance matrix (in m³/(kg.s²))
      */
     public double getCthrdrg() {
         return covarianceMatrix.getEntry(8, 6);
     }
 
     /**
      * Set the object [9,7] in covariance matrix (with index starting at 1).
      * @param CTHRDRG = object [9,7] in covariance matrix (in m³/(kg.s²))
      */
     public void setCthrdrg(final double CTHRDRG) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 6, CTHRDRG);
     }
 
     /**
      * Get the object [9,8] in covariance matrix (with index starting at 1).
      * @return the object [9,8] in covariance matrix (in m³/(kg.s²))
      */
     public double getCthrsrp() {
         return covarianceMatrix.getEntry(8, 7);
     }
 
     /**
      * Set the object [9,8] in covariance matrix (with index starting at 1).
      * @param CTHRSRP = object [9,8] in covariance matrix (in m³/(kg.s²))
      */
     public void setCthrsrp(final double CTHRSRP) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 7, CTHRSRP);
     }
 
     /**
      * Get the object [9,9] in covariance matrix (with index starting at 1).
      * @return the object [9,9] in covariance matrix (in m²/s⁴)
      */
     public double getCthrthr() {
         return covarianceMatrix.getEntry(8, 8);
     }
 
     /**
      * Set the object [9,9] in covariance matrix (with index starting at 1).
      * @param CTHRTHR = object [9,9] in covariance matrix (in m²/s⁴)
      */
     public void setCthrthr(final double CTHRTHR) {
         refuseFurtherComments();
         setCovarianceMatrixEntry(8, 8, CTHRTHR);
     }
 
 }