I brought this up in commons-math and it was determined that that probably wasn't a good place for it, as that lib focuses on computational functions. It was also mentioned that commons-numbers was not a great place for the static util method either.
Essentially the need for this relates to scientific measurements. Measurements are often reported with implied precision and uncertainty (e.g. 0.0015 has 2 significant figures, 1.10 has 3, etc). Currently there are no Number classes that retain or respect this information. There are widely accepted conventions for how to retain and adjust both precision and uncertainty during mathematical operations. But the first step is simply knowing what those two values are. I propose a util method (already written) in NumberUtils that can do this. The conventions are widely documented but would be spelled out very specifically in the javadoc. Although NumberUtils mainly focuses on pure math transformation, it does also include some parsing, so this doesn't seem to be *completely* out of scope. Is NumberUtils a possible home for this? On a separate, but related note, I honestly think this sort of math actually deserves a full blown java Number implementation (similar to BigFraction and Complex classes in commons- numbers). Possibly called BigMeasurement? Which can interact with other Number implementations as well as other BigMeasurements and retain/report the correct uncertainty and precision throughout the computation. I haven't ironed that out - but a necessary intermediate step is just being able to get the sigfig count. Dan
