HansenUtilities.java
/* Copyright 2002-2022 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.semianalytical.dsst.utilities.hansen;
import org.hipparchus.analysis.polynomials.PolynomialFunction;
/**
* Utilities class.
*
* @author Lucian Barbulescu
*/
public class HansenUtilities {
/** 1 represented as a polynomial. */
public static final PolynomialFunction ONE = new PolynomialFunction(new double[] {
1
});
/** 0 represented as a polynomial. */
public static final PolynomialFunction ZERO = new PolynomialFunction(new double[] {
0
});
/** Private constructor as class is a utility.
*/
private HansenUtilities() {
}
/**
* Build the identity matrix of order 2.
*
* <pre>
* / 1 0 \
* I₂ = | |
* \ 0 1 /
* </pre>
*
* @return the identity matrix of order 2
*/
public static final PolynomialFunctionMatrix buildIdentityMatrix2() {
final PolynomialFunctionMatrix matrix = new PolynomialFunctionMatrix(2);
matrix.setMatrix(new PolynomialFunction[][] {
{
ONE, ZERO
},
{
ZERO, ONE
}
});
return matrix;
}
/**
* Build the empty matrix of order 2.
*
* <pre>
* / 0 0 \
* E₂ = | |
* \ 0 0 /
* </pre>
*
* @return the identity matrix of order 2
*/
public static final PolynomialFunctionMatrix buildZeroMatrix2() {
final PolynomialFunctionMatrix matrix = new PolynomialFunctionMatrix(2);
matrix.setMatrix(new PolynomialFunction[][] {
{
ZERO, ZERO
},
{
ZERO, ZERO
}
});
return matrix;
}
/**
* Build the identity matrix of order 4.
*
* <pre>
* / 1 0 0 0 \
* | |
* | 0 1 0 0 |
* I₄ = | |
* | 0 0 1 0 |
* | |
* \ 0 0 0 1 /
* </pre>
*
* @return the identity matrix of order 4
*/
public static final PolynomialFunctionMatrix buildIdentityMatrix4() {
final PolynomialFunctionMatrix matrix = new PolynomialFunctionMatrix(4);
matrix.setMatrix(new PolynomialFunction[][] {
{
ONE, ZERO, ZERO, ZERO
},
{
ZERO, ONE, ZERO, ZERO
},
{
ZERO, ZERO, ONE, ZERO
},
{
ZERO, ZERO, ZERO, ONE
}
});
return matrix;
}
/**
* Build the empty matrix of order 4.
*
* <pre>
* / 0 0 0 0 \
* | |
* | 0 0 0 0 |
* E₄ = | |
* | 0 0 0 0 |
* | |
* \ 0 0 0 0 /
* </pre>
*
* @return the identity matrix of order 4
*/
public static final PolynomialFunctionMatrix buildZeroMatrix4() {
final PolynomialFunctionMatrix matrix = new PolynomialFunctionMatrix(4);
matrix.setMatrix(new PolynomialFunction[][] {
{
ZERO, ZERO, ZERO, ZERO
},
{
ZERO, ZERO, ZERO, ZERO
},
{
ZERO, ZERO, ZERO, ZERO
},
{
ZERO, ZERO, ZERO, ZERO
}
} );
return matrix;
}
}