[Info-vax] Floating Point, Machine Epsilon, Rust, Swift, Etc (was: Re: VMS Software Q1 '23 Update)

[Dan Cross]

In article <tre863$ecn5$1 at dont-email.me>,
Arne Vajhøj  <arne at vajhoej.dk> wrote:
>On 2/1/2023 11:52 AM, Stephen Hoffman wrote:
>> Swift has a deliberately-obscurely-named equivalent to machine epsilon, 
>> as do some other languages.
>
>The reality is that a relevant epsilon for floating point comparison
>depends on the context.
>
>When I am exposed to the problem then it is typical regarding
>testing for convergence of iterative algorithms. Is Xt
>the same as Xt-1.
>
>And the right epsilon depends on the scale of the data.

I interpreted Stephen Hoffman's mention of epsilon as
referring to the constant (e.g., in IEEE754 floating
point).  This is well defined for each representation.
https://en.wikipedia.org/wiki/Machine_epsilon

	- Dan C.