A computer-implemented method of providing a filter (F) in a neural processing unit comprises: receiving input corresponding to target dimensions (XT, YT) of the filter; receiving input corresponding to sub-filter dimensions (X1 . . . n′, Y1 . . . n′) of each of a plurality of sub-filters (SF1 . . . n) implementable in the neural processing unit; and defining the filter (F) as a combination of the plurality of sub-filters (SF1 . . . n), the combination having dimensions that equate to the target dimensions (XT, YT), and wherein the sub-filter dimensions (X1 . . . n′, Y1 . . . n′) of at least two of the sub-filters in the combination are unequal.