In re Iwahashi, 888 F.2d 1370, 12 U.S.P.Q.2d (BNA) 1908 (Fed. Cir. 1989) (full-text).
Factual Background Edit
The invention involved an electronic "unit" for providing coefficients to be used in pattern recognition based on input values. The method in the prior art was based on a formula involving a multiplication step. The improvement was based on the fact that a close approximation of the correct coefficient values could be obtained without multiplication by using instead a stated formula. This eliminated circuitry necessary to perform the multiplication function. All of the elements in the claim were in means-plus-function form, except for a read-only memory containing certain necessary values.
Federal Circuit Proceedings Edit
The Federal Circuit found that while the claim recited a mathematical algorithm, the preemption aspect of the two-part test was not met because the mathematical algorithm was physically implemented to define structural relationships between physical elements of the claim. Even though the read-only memory unit in the computer stored a mathematical formula for calculating the square of numbers, the claim defined more than a mathematical algorithm. The Federal Circuit reversed a finding of nonstatutory subject matter.