An apparatus includes circuits including a first circuit and a second circuit, each circuit including subarrays of magnetic tunnel junctions, where: (1) the magnetic tunnel junctions in each subarray are arranged in rows, the magnetic tunnel junctions in each row are connected in series, and the rows are connected in parallel; and (2) the subarrays are connected in series. The apparatus further comprises a field line configured to generate a first magnetic field for configuring an operating point of the first circuit based on a current flow through the field line, where the impedance of a subset of the plurality of rows in each subarray of magnetic tunnel junctions included in the first circuit is configured based on the first magnetic field.