The invention provides a catalyst system comprising: a transition metal bisphenolate catalyst and another olefin polymerization catalyst, and optionally a co-catalyst, e. An upper and a lower cage surface include a first lordosis angle in the direction front part-rear part and a second lordosis angle perpendicular thereto, said cage surfaces intersecting outside the cage. The input values are filtered using a non-linear filtering operation to produce respective shaped values, and the shaped values are converted to output values using a linear spreading transformation with coefficients chosen so that each of the shaped values contributes to at least two of the output values. Accordingly, it is possible to control power consumption of the 3D graphics accelerator while maintaining performance at or above a given level.