Example usage for org.apache.commons.math3.analysis.differentiation DerivativeStructure negate

Introduction

In this page you can find the example usage for org.apache.commons.math3.analysis.differentiation DerivativeStructure negate.

Prototype

public DerivativeStructure negate() 

Source Link

Document

unary '-' operator.

Usage

From source file:org.orekit.forces.BoxAndSolarArraySpacecraft.java

/** {@inheritDoc} */
public FieldVector3D<DerivativeStructure> radiationPressureAcceleration(final AbsoluteDate date,
        final Frame frame, final FieldVector3D<DerivativeStructure> position,
        final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass,
        final FieldVector3D<DerivativeStructure> flux) throws OrekitException {

    if (flux.getNormSq().getValue() < Precision.SAFE_MIN) {
        // null illumination (we are probably in umbra)
        return new FieldVector3D<DerivativeStructure>(0.0, flux);
    }//from  w w  w .ja va 2  s . co  m

    // radiation flux in spacecraft frame
    final FieldVector3D<DerivativeStructure> fluxSat = rotation.applyTo(flux);

    // solar array contribution
    FieldVector3D<DerivativeStructure> normal = getNormal(date, frame, position, rotation);
    DerivativeStructure dot = FieldVector3D.dotProduct(normal, fluxSat);
    if (dot.getValue() > 0) {
        // the solar array is illuminated backward,
        // fix signs to compute contribution correctly
        dot = dot.negate();
        normal = normal.negate();
    }
    FieldVector3D<DerivativeStructure> force = facetRadiationAcceleration(normal, solarArrayArea, fluxSat, dot);

    // body facets contribution
    for (final Facet bodyFacet : facets) {
        normal = new FieldVector3D<DerivativeStructure>(mass.getField().getOne(), bodyFacet.getNormal());
        dot = FieldVector3D.dotProduct(normal, fluxSat);
        if (dot.getValue() < 0) {
            // the facet intercepts the incoming flux
            force = force.add(facetRadiationAcceleration(normal, bodyFacet.getArea(), fluxSat, dot));
        }
    }

    // convert to inertial frame
    return rotation.applyInverseTo(new FieldVector3D<DerivativeStructure>(mass.reciprocal(), force));

}

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