According to examples, an apparatus may include a processor and a non-transitory computer readable medium having instructions that when executed by the processor, may cause the processor to partition a matrix of elements into a plurality of sub-matrices of elements. Each sub-matrix of the plurality of sub-matrices may include elements from a set of columns of the matrix of elements that includes a nonzero element. The processor may also assign elements of the plurality of sub-matrices to a plurality of crossbar devices to maximize a number of nonzero elements of the matrix of elements assigned to the crossbar devices.