Examples with FiniteDifferencesDifferentiator org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator used on opensource projects

Example 6 with FiniteDifferencesDifferentiator

use of org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator in project Orekit by CS-SI.

the class PVCoordinatesTest method testNormalize.

@Test
public void testNormalize() {
    DSFactory factory = new DSFactory(1, 2);
    RandomGenerator generator = new Well19937a(0xb2011ffd25412067l);
    FiniteDifferencesDifferentiator differentiator = new FiniteDifferencesDifferentiator(5, 1.0e-3);
    for (int i = 0; i < 200; ++i) {
        final PVCoordinates pv = randomPVCoordinates(generator, 1e6, 1e3, 1.0);
        DerivativeStructure x = differentiator.differentiate(new UnivariateFunction() {

            public double value(double t) {
                return pv.shiftedBy(t).getPosition().normalize().getX();
            }
        }).value(factory.variable(0, 0.0));
        DerivativeStructure y = differentiator.differentiate(new UnivariateFunction() {

            public double value(double t) {
                return pv.shiftedBy(t).getPosition().normalize().getY();
            }
        }).value(factory.variable(0, 0.0));
        DerivativeStructure z = differentiator.differentiate(new UnivariateFunction() {

            public double value(double t) {
                return pv.shiftedBy(t).getPosition().normalize().getZ();
            }
        }).value(factory.variable(0, 0.0));
        PVCoordinates normalized = pv.normalize();
        Assert.assertEquals(x.getValue(), normalized.getPosition().getX(), 1.0e-16);
        Assert.assertEquals(y.getValue(), normalized.getPosition().getY(), 1.0e-16);
        Assert.assertEquals(z.getValue(), normalized.getPosition().getZ(), 1.0e-16);
        Assert.assertEquals(x.getPartialDerivative(1), normalized.getVelocity().getX(), 3.0e-13);
        Assert.assertEquals(y.getPartialDerivative(1), normalized.getVelocity().getY(), 3.0e-13);
        Assert.assertEquals(z.getPartialDerivative(1), normalized.getVelocity().getZ(), 3.0e-13);
        Assert.assertEquals(x.getPartialDerivative(2), normalized.getAcceleration().getX(), 6.0e-10);
        Assert.assertEquals(y.getPartialDerivative(2), normalized.getAcceleration().getY(), 6.0e-10);
        Assert.assertEquals(z.getPartialDerivative(2), normalized.getAcceleration().getZ(), 6.0e-10);
    }
}

Example 7 with FiniteDifferencesDifferentiator

use of org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator in project Orekit by CS-SI.

the class IERSConventionsTest method checkGMSTRate.

private void checkGMSTRate(final TimeScalarFunction gmst, final TimeScalarFunction gmstRate, final AbsoluteDate date, final double span, final double sampleStep, final double h, final double tolerance) throws OrekitException {
    UnivariateDifferentiableFunction differentiated = new FiniteDifferencesDifferentiator(4, h).differentiate(new UnivariateFunction() {

        @Override
        public double value(final double dt) {
            return gmst.value(date.shiftedBy(dt));
        }
    });
    DSFactory factory = new DSFactory(1, 1);
    double maxRateError = 0;
    for (double dt = 0; dt < span; dt += sampleStep) {
        double rateRef = differentiated.value(factory.variable(0, dt)).getPartialDerivative(1);
        double rate = gmstRate.value(date.shiftedBy(dt));
        maxRateError = FastMath.max(maxRateError, FastMath.abs(rateRef - rate));
    }
    Assert.assertEquals(0, maxRateError, tolerance);
}

Example 8 with FiniteDifferencesDifferentiator

use of org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator in project Orekit by CS-SI.

the class CartesianOrbitTest method differentiate.

private <S extends Function<CartesianOrbit, Double>> double differentiate(TimeStampedPVCoordinates pv, Frame frame, double mu, S picker) {
    final DSFactory factory = new DSFactory(1, 1);
    FiniteDifferencesDifferentiator differentiator = new FiniteDifferencesDifferentiator(8, 0.1);
    UnivariateDifferentiableFunction diff = differentiator.differentiate(new UnivariateFunction() {

        public double value(double dt) {
            return picker.apply(new CartesianOrbit(pv.shiftedBy(dt), frame, mu));
        }
    });
    return diff.value(factory.variable(0, 0.0)).getPartialDerivative(1);
}

Example 9 with FiniteDifferencesDifferentiator

use of org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator in project Orekit by CS-SI.

the class CircularOrbitTest method differentiate.

private <S extends Function<CircularOrbit, Double>> double differentiate(TimeStampedPVCoordinates pv, Frame frame, double mu, S picker) {
    final DSFactory factory = new DSFactory(1, 1);
    FiniteDifferencesDifferentiator differentiator = new FiniteDifferencesDifferentiator(8, 0.1);
    UnivariateDifferentiableFunction diff = differentiator.differentiate(new UnivariateFunction() {

        public double value(double dt) {
            return picker.apply(new CircularOrbit(pv.shiftedBy(dt), frame, mu));
        }
    });
    return diff.value(factory.variable(0, 0.0)).getPartialDerivative(1);
}

Example 10 with FiniteDifferencesDifferentiator

use of org.hipparchus.analysis.differentiation.FiniteDifferencesDifferentiator in project Orekit by CS-SI.

the class FieldCircularOrbitTest method differentiate.

private <T extends RealFieldElement<T>, S extends Function<FieldCircularOrbit<T>, T>> double differentiate(TimeStampedFieldPVCoordinates<T> pv, Frame frame, double mu, S picker) {
    final DSFactory factory = new DSFactory(1, 1);
    FiniteDifferencesDifferentiator differentiator = new FiniteDifferencesDifferentiator(8, 0.1);
    UnivariateDifferentiableFunction diff = differentiator.differentiate(new UnivariateFunction() {

        public double value(double dt) {
            return picker.apply(new FieldCircularOrbit<>(pv.shiftedBy(dt), frame, mu)).getReal();
        }
    });
    return diff.value(factory.variable(0, 0.0)).getPartialDerivative(1);
}