RFR: 8315024: Vector API FP reduction tests should not test for exact equality

[Emanuel Peter]

On Thu, 5 Oct 2023 14:00:48 GMT, Gergö Barany <gbarany at openjdk.org> wrote:

>> test/jdk/jdk/incubator/vector/Double128VectorTests.java line 64:
>> 
>>> 62: 
>>> 63:     // for floating point reduction ops that may introduce rounding errors
>>> 64:     private static final double RELATIVE_ROUNDING_ERROR = (double)0.01;
>> 
>> It seems a bit large. Have you tried to make it smaller? Or what is your justification for this value?
>
> With the current version of the test, a value as small as 0.000001 seems to be fine, one more zero is too small. This will probably have to be adjusted in the future for larger tests.

I'm just worried that 1% is very much for the addition tests. Basically we might be dropping off a whole element, and would not notice it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16024#discussion_r1348350546