4. The storage medium as set forth in claim 1 , wherein the summation of exponentials is of the form ∑ k = 1 K ⁢ ⅇ β k T ⁢ x and the operation of constructing an upper bound using a double majorization bounding process comprises first and second majorization processes comprising: upper bounding the summation of exponentials by a product of sigmoid functions; and employing a bound on log(1+e x ) in the upper bounding of the summation of exponentials of the form ∑ k = 1 K ⁢ ⅇ β k T ⁢ x .
5. The storage medium as set forth in claim 4 , wherein the first majorization process generates an upper bound of the form: log ⁢ ∑ k = 1 K ⁢ ⅇ x k ≤ α + ∑ k = 1 K ⁢ log ⁡ ( 1 + ⅇ x k - α ) where ⁢ ⁢ α ∈ K .