A phase-change memory cell includes a phase change material; a reference electrical terminal disposed on first side of the phase change material; first and second electrical terminals disposed on a second side of the phase change material; the phase-change material configured to be reversibly transformable between an amorphous phase and a crystalline phase, in response to a phase-altering electrical signal applied to the phase-change material via the reference electrical terminal and one or more of the first and second electrical terminals; a resistance measurement unit configured to measure a respective electrical resistance between each of the first and electrical terminals and the reference electrical terminal; and a mathematical operation unit configured to determine a mathematical relation between the respective electrical resistances measured between each of the electrical terminals and the reference electrical terminal.