> > > > > > More nitpicking. I don't see that multiplying top and bottom by > values.length > > makes things better. In fact, it could reduce precision by inflating the > > magnitude of the first term before subtracting from it and dividing it. > > > > hmm, good points. this may be an example of where "consolidating > division operations" to limit the amount of division going on does not > necessarily lead to a better algorithm. Its general practice to > consolidate division operations to produce a more efficient algorithm > where ever possible.
These kinds of statements need to be substantiated from a numerical analysis standpoint. I would like to suggest that from this point forward all assertions about numerical stability or "best practices" in numerical computing using J2SE be accompanied by references to definitive sources. Now I have my doubts that its proper to do from > what you've suggested. Yes, its optimized an will be a faster > calculation ("values.length" fewer expensive divisions) , but it will be > less accurate as you've suggested. Accuracy should probably be weighted > of greater importance than efficiency in much of our work. That is a debatable assertion. The best approach is to actually do the analysis to determine exactly what the computational cost difference is, examine the use cases and make a decision on what to implement and whether or not to give the user a choice. > > > Also, do we really need the explicit casts to double? It seems to me that > the > > numerators are doubles, so the whole calculation will be double. > > > > It may be an artifact from learning to program in other languages and > not truly understanding type conversion in java arithmetic. Is it the > case that in double/int --> double the int is converted to a double > *prior* to the division occurring. I remember a discussion where it was > recommended by others in the group to explicitly cast int's to double's > in algorithms as a best practice. > Omitting explicit casts has caused us problems in the past. I suggest that we continue to follow the practice of adding them. Phil > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]