Examples disclosed herein include a dot product engine, which includes a resistive memory array to receive an input vector, perform a dot product operation on the input vector and a stored vector stored in the memory array, and output an analog signal representing a result of the dot product operation. The dot product engine includes a stored negation indicator to indicate whether elements of the stored vector have been negated, and a digital circuit to generate a digital dot product result value based on the analog signal and the stored negation indicator.