Described are computer-implemented methods and apparatuses, including computer program products, for estimating an optimal value for each input factor of a design space. The design space is defined by the input factors and output responses for a physical process. The optimal values for the input factors represent a starting point for estimating the design space. Data is received for the input factors, the output responses and criteria. An initial design space is estimated based on the received data. The optimal values for the input factors are determined from the initial design space.