Piece-wise linear approximation.

<p>A piece-wise linear approximation (PLA) is shown in green. It is computed by linearly interpolating the grid points in which the upper and lower bounds of the evaluation function may be computed more precisely as the minimum resp. maximum of the values from all parameter subintervals sharing boundary grid points. The obtained result is more precise than the original min-max approximation (in purple), albeit without the conservative guarantee on bounds.