List of usage examples for org.apache.commons.math3.analysis.differentiation DerivativeStructure getOrder
public int getOrder()
From source file:org.orekit.forces.drag.DragForce.java
/** {@inheritDoc} */ public FieldVector3D<DerivativeStructure> accelerationDerivatives(final AbsoluteDate date, final Frame frame, final FieldVector3D<DerivativeStructure> position, final FieldVector3D<DerivativeStructure> velocity, final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass) throws OrekitException { // retrieve derivation properties final int parameters = mass.getFreeParameters(); final int order = mass.getOrder(); // get atmosphere properties in atmosphere own frame final Frame atmFrame = atmosphere.getFrame(); final Transform toBody = frame.getTransformTo(atmFrame, date); final FieldVector3D<DerivativeStructure> posBodyDS = toBody.transformPosition(position); final Vector3D posBody = posBodyDS.toVector3D(); final double rho = atmosphere.getDensity(date, posBody, atmFrame); final Vector3D vAtmBody = atmosphere.getVelocity(date, posBody, atmFrame); // we consider that at first order the atmosphere velocity in atmosphere frame // does not depend on local position; however atmosphere velocity in inertial // frame DOES depend on position since the transform between the frames depends // on it, due to central body rotation rate and velocity composition. // So we use the transform to get the correct partial derivatives on vAtm final FieldVector3D<DerivativeStructure> vAtmBodyDS = new FieldVector3D<DerivativeStructure>( new DerivativeStructure(parameters, order, vAtmBody.getX()), new DerivativeStructure(parameters, order, vAtmBody.getY()), new DerivativeStructure(parameters, order, vAtmBody.getZ())); final FieldPVCoordinates<DerivativeStructure> pvAtmBody = new FieldPVCoordinates<DerivativeStructure>( posBodyDS, vAtmBodyDS);/*from w ww.j av a 2 s . c o m*/ final FieldPVCoordinates<DerivativeStructure> pvAtm = toBody.getInverse().transformPVCoordinates(pvAtmBody); // now we can compute relative velocity, it takes into account partial derivatives with respect to position final FieldVector3D<DerivativeStructure> relativeVelocity = pvAtm.getVelocity().subtract(velocity); // compute acceleration with all its partial derivatives return spacecraft.dragAcceleration(date, frame, position, rotation, mass, rho, relativeVelocity); }
From source file:org.orekit.forces.gravity.HolmesFeatherstoneAttractionModel.java
/** {@inheritDoc} */ public FieldVector3D<DerivativeStructure> accelerationDerivatives(final AbsoluteDate date, final Frame frame, final FieldVector3D<DerivativeStructure> position, final FieldVector3D<DerivativeStructure> velocity, final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass) throws OrekitException { // get the position in body frame final Transform fromBodyFrame = bodyFrame.getTransformTo(frame, date); final Transform toBodyFrame = fromBodyFrame.getInverse(); final Vector3D positionBody = toBodyFrame.transformPosition(position.toVector3D()); // compute gradient and Hessian final GradientHessian gh = gradientHessian(date, positionBody); // gradient of the non-central part of the gravity field final double[] gInertial = fromBodyFrame.transformVector(new Vector3D(gh.getGradient())).toArray(); // Hessian of the non-central part of the gravity field final RealMatrix hBody = new Array2DRowRealMatrix(gh.getHessian(), false); final RealMatrix rot = new Array2DRowRealMatrix(toBodyFrame.getRotation().getMatrix()); final RealMatrix hInertial = rot.transpose().multiply(hBody).multiply(rot); // distribute all partial derivatives in a compact acceleration vector final int parameters = mass.getFreeParameters(); final int order = mass.getOrder(); final double[] derivatives = new double[1 + parameters]; final DerivativeStructure[] accDer = new DerivativeStructure[3]; for (int i = 0; i < 3; ++i) { // first element is value of acceleration (i.e. gradient of field) derivatives[0] = gInertial[i];//from www . java 2s .com // next three elements are one row of the Jacobian of acceleration (i.e. Hessian of field) derivatives[1] = hInertial.getEntry(i, 0); derivatives[2] = hInertial.getEntry(i, 1); derivatives[3] = hInertial.getEntry(i, 2); // next elements (three or four depending on mass being used or not) are left as 0 accDer[i] = new DerivativeStructure(parameters, order, derivatives); } return new FieldVector3D<DerivativeStructure>(accDer); }
From source file:org.orekit.forces.maneuvers.ConstantThrustManeuver.java
/** {@inheritDoc} */ public FieldVector3D<DerivativeStructure> accelerationDerivatives(final AbsoluteDate date, final Frame frame, final FieldVector3D<DerivativeStructure> position, final FieldVector3D<DerivativeStructure> velocity, final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass) throws OrekitException { if (firing) { return new FieldVector3D<DerivativeStructure>(mass.reciprocal().multiply(thrust), rotation.applyInverseTo(direction)); } else {/* w w w . java2 s .co m*/ // constant (and null) acceleration when not firing final int parameters = mass.getFreeParameters(); final int order = mass.getOrder(); return new FieldVector3D<DerivativeStructure>(new DerivativeStructure(parameters, order, 0.0), new DerivativeStructure(parameters, order, 0.0), new DerivativeStructure(parameters, order, 0.0)); } }
From source file:org.orekit.propagation.numerical.Jacobianizer.java
/** Compute acceleration and derivatives with respect to state. * @param date current date//w ww . j a v a 2 s . com * @param frame inertial reference frame for state (both orbit and attitude) * @param position position of spacecraft in reference frame * @param velocity velocity of spacecraft in reference frame * @param rotation orientation (attitude) of the spacecraft with respect to reference frame * @param mass spacecraft mass * @return acceleration with derivatives * @exception OrekitException if the underlying force models cannot compute the acceleration */ public FieldVector3D<DerivativeStructure> accelerationDerivatives(final AbsoluteDate date, final Frame frame, final FieldVector3D<DerivativeStructure> position, final FieldVector3D<DerivativeStructure> velocity, final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass) throws OrekitException { final int parameters = mass.getFreeParameters(); final int order = mass.getOrder(); // estimate the scalar velocity step, assuming energy conservation // and hence differentiating equation V = sqrt(mu (2/r - 1/a)) final Vector3D p0 = position.toVector3D(); final Vector3D v0 = velocity.toVector3D(); final double r2 = p0.getNormSq(); final double hVel = mu * hPos / (v0.getNorm() * r2); // estimate mass step, applying the same relative value as position final double hMass = mass.getValue() * hPos / FastMath.sqrt(r2); // compute nominal acceleration final AccelerationRetriever nominal = new AccelerationRetriever(); computeShiftedAcceleration(nominal, date, frame, p0, v0, rotation.toRotation(), mass.getValue()); final double[] a0 = nominal.getAcceleration().toArray(); // compute accelerations with shifted states final AccelerationRetriever shifted = new AccelerationRetriever(); // shift position by hPos alon x, y and z computeShiftedAcceleration(shifted, date, frame, shift(position, 0, hPos), v0, shift(rotation, 0, hPos), shift(mass, 0, hPos)); final double[] derPx = new Vector3D(1 / hPos, shifted.getAcceleration(), -1 / hPos, nominal.getAcceleration()).toArray(); computeShiftedAcceleration(shifted, date, frame, shift(position, 1, hPos), v0, shift(rotation, 1, hPos), shift(mass, 1, hPos)); final double[] derPy = new Vector3D(1 / hPos, shifted.getAcceleration(), -1 / hPos, nominal.getAcceleration()).toArray(); computeShiftedAcceleration(shifted, date, frame, shift(position, 2, hPos), v0, shift(rotation, 2, hPos), shift(mass, 2, hPos)); final double[] derPz = new Vector3D(1 / hPos, shifted.getAcceleration(), -1 / hPos, nominal.getAcceleration()).toArray(); // shift velocity by hVel alon x, y and z computeShiftedAcceleration(shifted, date, frame, p0, shift(velocity, 3, hVel), shift(rotation, 3, hVel), shift(mass, 3, hVel)); final double[] derVx = new Vector3D(1 / hVel, shifted.getAcceleration(), -1 / hVel, nominal.getAcceleration()).toArray(); computeShiftedAcceleration(shifted, date, frame, p0, shift(velocity, 4, hVel), shift(rotation, 4, hVel), shift(mass, 4, hVel)); final double[] derVy = new Vector3D(1 / hVel, shifted.getAcceleration(), -1 / hVel, nominal.getAcceleration()).toArray(); computeShiftedAcceleration(shifted, date, frame, p0, shift(velocity, 5, hVel), shift(rotation, 5, hVel), shift(mass, 5, hVel)); final double[] derVz = new Vector3D(1 / hVel, shifted.getAcceleration(), -1 / hVel, nominal.getAcceleration()).toArray(); final double[] derM; if (parameters < 7) { derM = null; } else { // shift mass by hMass computeShiftedAcceleration(shifted, date, frame, p0, v0, shift(rotation, 6, hMass), shift(mass, 6, hMass)); derM = new Vector3D(1 / hMass, shifted.getAcceleration(), -1 / hMass, nominal.getAcceleration()) .toArray(); } final double[] derivatives = new double[1 + parameters]; final DerivativeStructure[] accDer = new DerivativeStructure[3]; for (int i = 0; i < 3; ++i) { // first element is value of acceleration derivatives[0] = a0[i]; // next three elements are derivatives with respect to position derivatives[1] = derPx[i]; derivatives[2] = derPy[i]; derivatives[3] = derPz[i]; // next three elements are derivatives with respect to velocity derivatives[4] = derVx[i]; derivatives[5] = derVy[i]; derivatives[6] = derVz[i]; if (derM != null) { derivatives[7] = derM[i]; } accDer[i] = new DerivativeStructure(parameters, order, derivatives); } return new FieldVector3D<DerivativeStructure>(accDer); }