  In design of optical systems based on LED (Light emitting diode) technology,
a crucial task is to handle the unstructured data describing properties of
optical elements in standard formats. This leads to the problem of data fitting
within an appropriate model. Newton's method is used as an upgrade of
previously developed most promising discrete optimization heuristics showing
improvement of both performance and quality of solutions. Experiment also
indicates that a combination of an algorithm that finds promising initial
solutions as a preprocessor to Newton's method may be a winning idea, at least
on some datasets of instances.
