US Patent 7979360 Error propagation in calculation with conditional alternatives

The result of a first calculation may be determined by one of two alternative calculations. Each of the alternative calculations has an error associated therewith (due to factors such as measurement imprecision, rounding, etc.), and these errors propagate to the first calculation. However, there may also be error in the first calculation due to uncertainty about which of the alternative calculations applies. Such error can be taken into account based on the respective probabilities that the first and second calculations will apply, as well as the difference in the results produced by the two calculations.