Well, true, I'm not in favor of rearranging +/ either. The dangers of
floating point don't include nondeterminism, unless you make them.

However, I also think matrix products have it worse. Numbers with widely
varying exponents are a bit of an edge case. But when you're multiplying
a few large matrices together they can show up naturally, so I expect
it's not so rare to have a product that's numerically stable in one
direction and not in the other.

Marshall

On Mon, Jan 09, 2023 at 05:52:34PM -0600, Omar Antolín Camarena wrote:
> But that's just normal floating non-associativity. It happens even for 
> addition of "integers":
> 
>    1 + (_1e19 + 1e19)
> 1
>    (1 + _1e19) + 1e19
> 0
> 
> People using floating point are probably aware of the dangers or at least 
> should be.
> 
> -- 
> Omar
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