1. A method for training a program by optimizing a set of program parameter values, comprising optimizing the parameter values using the Newton's algorithm, wherein successive updates of the parameter values are provided by a method of conjugate residuals, which computes each of the successive updates by solving a set of linear equations involving a Hessian matrix and a gradient vector.
3. A method as in claim 1 , wherein the method of conjugate residuals terminates the β parameter in the method of conjugate residuals has an absolute value that is not less than a pre-determined constant value.