1. A computer-implemented method for variant configuration, comprising: using a computer, loading a dependency tree comprising Boolean expressions describing an input selection condition into memory in one of disjunctive normal form (DNF) and conjunctive normal form (CNF); joining concrete configuration values from input configuration data with the dependency tree, and comparing values of one or more literals; aggregating the comparison results and aggregating the aggregation results, using an AND-group with a minimum function and an OR-group with a maximum function in an alternating sequence ordered corresponding to the chosen normal form; and outputting the result of the selection condition evaluation for the concrete configuration; wherein each separate branch of the dependency tree comprises Boolean expressions selectively cast in one of DNF and CNF according to which normal form most reduces the number of Boolean expressions in each branch.