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by mkbosmans 1390 days ago
> Unlike using either underflow exceptions or subnormals, the use of flush-to-zero and denormals-are-zero > is acceptable only in the programs where computation errors do not matter at all, such as games.

That is not true. FTZ and DAZ are perfectly reasonable in a lot of scientific computing scenario's, where computation errors in general are closely scrutinized.

1 comments

It depends on what is meant by "scrutinized".

FTZ and DAZ and any other methods that are certain to introduce errors can be accepted only inside a computation for which there is an independent way to verify the results and that way is always used, without exceptions.

For example, it is indeed OK to use FTZ and DAZ when solving a system of equations, if, and only if, after obtaining a solution it is inserted in the original equations and a residual error is computed, this time without using FTZ and DAZ, and an excessive residual error triggers an appropriate means of notifying the user about the failure.