* supporting the 1d case for now.
*/
final Vector Hv = H.convertToVector();
final Matrix postAInv = priorAInv.plus(Hv.outerProduct(Hv)).inverse();
// TODO FIXME: ewww. inverse.
final Vector postPhiMean = postAInv.times(priorAInv.times(phiPriorSmpl).plus(
H.transpose().times(postStateSample)));
final MultivariateGaussian postPhi = systemOffsetsSS.get(predState.getClassId());
postPhi.setMean(postPhiMean);
postPhi.setCovariance(postAInv.scale(newInvScaleSmpl));