Review

class NordsieckStepInterpolator {
    /** Reinitialize the instance.
     * <p>Beware that all arrays <em>must</em> be references to integrator
     * arrays, in order to ensure proper update without copy.</p>
     * @param time time at which all arrays are defined
     * @param stepSize step size used in the scaled and nordsieck arrays
     * @param scaledDerivative reference to the integrator array holding the first
     * scaled derivative
     * @param nordsieckVector reference to the integrator matrix holding the
     * nordsieck vector
     */
    public void reinitialize(final double time, final double stepSize,
                             final double[] scaledDerivative,
                             final Array2DRowRealMatrix nordsieckVector) {
        this.referenceTime = time;
        this.scalingH      = stepSize;
        this.scaled        = scaledDerivative;
        this.nordsieck     = nordsieckVector;

        // make sure the state and derivatives will depend on the new arrays
        setInterpolatedTime(getInterpolatedTime());

    }

}