Example usage for org.apache.commons.math3.ode.nonstiff DormandPrince853Integrator setInitialStepSize

Introduction

In this page you can find the example usage for org.apache.commons.math3.ode.nonstiff DormandPrince853Integrator setInitialStepSize.

Prototype

public void setInitialStepSize(final double initialStepSize) 

Source Link

Document

Set the initial step size.

Usage

From source file:fr.cs.examples.bodies.Phasing.java

private void run(final File input)
        throws IOException, IllegalArgumentException, ParseException, OrekitException {

    // read input parameters
    KeyValueFileParser<ParameterKey> parser = new KeyValueFileParser<ParameterKey>(ParameterKey.class);
    parser.parseInput(new FileInputStream(input));
    TimeScale utc = TimeScalesFactory.getUTC();

    // simulation properties
    AbsoluteDate date = parser.getDate(ParameterKey.ORBIT_DATE, utc);
    int nbOrbits = parser.getInt(ParameterKey.PHASING_ORBITS_NUMBER);
    int nbDays = parser.getInt(ParameterKey.PHASING_DAYS_NUMBER);
    double latitude = parser.getAngle(ParameterKey.SUN_SYNCHRONOUS_REFERENCE_LATITUDE);
    boolean ascending = parser.getBoolean(ParameterKey.SUN_SYNCHRONOUS_REFERENCE_ASCENDING);
    double mst = parser.getTime(ParameterKey.SUN_SYNCHRONOUS_MEAN_SOLAR_TIME).getSecondsInDay() / 3600;
    int degree = parser.getInt(ParameterKey.GRAVITY_FIELD_DEGREE);
    int order = parser.getInt(ParameterKey.GRAVITY_FIELD_ORDER);
    String gridOutput = parser.getString(ParameterKey.GRID_OUTPUT);
    double[] gridLatitudes = new double[] { parser.getAngle(ParameterKey.GRID_LATITUDE_1),
            parser.getAngle(ParameterKey.GRID_LATITUDE_2), parser.getAngle(ParameterKey.GRID_LATITUDE_3),
            parser.getAngle(ParameterKey.GRID_LATITUDE_4), parser.getAngle(ParameterKey.GRID_LATITUDE_5) };
    boolean[] gridAscending = new boolean[] { parser.getBoolean(ParameterKey.GRID_ASCENDING_1),
            parser.getBoolean(ParameterKey.GRID_ASCENDING_2), parser.getBoolean(ParameterKey.GRID_ASCENDING_3),
            parser.getBoolean(ParameterKey.GRID_ASCENDING_4),
            parser.getBoolean(ParameterKey.GRID_ASCENDING_5) };

    gravityField = GravityFieldFactory.getNormalizedProvider(degree, order);

    // initial guess for orbit
    CircularOrbit orbit = guessOrbit(date, FramesFactory.getEME2000(), nbOrbits, nbDays, latitude, ascending,
            mst);// w ww  .  j  a  va  2 s .  c  om
    System.out.println("initial orbit: " + orbit);
    System.out.println("please wait while orbit is adjusted...");
    System.out.println();

    // numerical model for improving orbit
    double[][] tolerances = NumericalPropagator.tolerances(0.1, orbit, OrbitType.CIRCULAR);
    DormandPrince853Integrator integrator = new DormandPrince853Integrator(1.0e-4 * orbit.getKeplerianPeriod(),
            1.0e-1 * orbit.getKeplerianPeriod(), tolerances[0], tolerances[1]);
    integrator.setInitialStepSize(1.0e-2 * orbit.getKeplerianPeriod());
    NumericalPropagator propagator = new NumericalPropagator(integrator);
    propagator.addForceModel(new HolmesFeatherstoneAttractionModel(
            FramesFactory.getGTOD(IERSConventions.IERS_2010, true), gravityField));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getSun()));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getMoon()));

    double deltaP = Double.POSITIVE_INFINITY;
    double deltaV = Double.POSITIVE_INFINITY;

    int counter = 0;
    DecimalFormat f = new DecimalFormat("0.000E00", new DecimalFormatSymbols(Locale.US));
    while (deltaP > 3.0e-1 || deltaV > 3.0e-4) {

        CircularOrbit previous = orbit;

        CircularOrbit tmp1 = improveEarthPhasing(previous, nbOrbits, nbDays, propagator);
        CircularOrbit tmp2 = improveSunSynchronization(tmp1, nbOrbits * tmp1.getKeplerianPeriod(), latitude,
                ascending, mst, propagator);
        orbit = improveFrozenEccentricity(tmp2, nbOrbits * tmp2.getKeplerianPeriod(), propagator);
        double da = orbit.getA() - previous.getA();
        double dex = orbit.getCircularEx() - previous.getCircularEx();
        double dey = orbit.getCircularEy() - previous.getCircularEy();
        double di = FastMath.toDegrees(orbit.getI() - previous.getI());
        double dr = FastMath.toDegrees(
                orbit.getRightAscensionOfAscendingNode() - previous.getRightAscensionOfAscendingNode());
        System.out.println(" iteration " + (++counter) + ": deltaA = " + f.format(da) + " m, deltaEx = "
                + f.format(dex) + ", deltaEy = " + f.format(dey) + ", deltaI = " + f.format(di)
                + " deg, deltaRAAN = " + f.format(dr) + " deg");

        PVCoordinates delta = new PVCoordinates(previous.getPVCoordinates(), orbit.getPVCoordinates());
        deltaP = delta.getPosition().getNorm();
        deltaV = delta.getVelocity().getNorm();

    }

    // final orbit
    System.out.println();
    System.out.println("final orbit (osculating): " + orbit);

    // generate the ground track grid file
    PrintStream output = new PrintStream(new File(input.getParent(), gridOutput));
    for (int i = 0; i < gridLatitudes.length; ++i) {
        printGridPoints(output, gridLatitudes[i], gridAscending[i], orbit, propagator, nbOrbits);
    }
    output.close();

}

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From source file:org.orekit.utils.SecularAndHarmonicTest.java

private NumericalPropagator createPropagator(CircularOrbit orbit) throws OrekitException {
    OrbitType type = OrbitType.CIRCULAR;
    double[][] tolerances = NumericalPropagator.tolerances(0.1, orbit, type);
    DormandPrince853Integrator integrator = new DormandPrince853Integrator(1.0, 600, tolerances[0],
            tolerances[1]);//from www.  j ava 2s  . c o  m
    integrator.setInitialStepSize(60.0);
    NumericalPropagator propagator = new NumericalPropagator(integrator);
    propagator.addForceModel(new HolmesFeatherstoneAttractionModel(earth.getBodyFrame(), gravityField));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getSun()));
    propagator.addForceModel(new ThirdBodyAttraction(CelestialBodyFactory.getMoon()));
    propagator.setOrbitType(type);
    propagator.resetInitialState(new SpacecraftState(orbit));
    return propagator;
}

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