solveCoef.RdThe squared length of the intermediate solution is attached as an attribute of the returned value.
solveCoef(predM, ...)prediction module, i.e. from class
predModule.
potentially further arguments used in methods; not used currently.
coefficient vector or increment of coef.~vector.
signature(predM = "dPredModule")..
signature(predM = "sPredModule")..
## TODO