# Aw: Re: Re: no tests for trigonometric functions? need help / hints how to adapt tests for gnumeric 'long' version,

• From: newbie nullzwei <newbie-02 gmx de>
• To: Gnumeric Forum <gnumeric-list gnome org>
• Subject: Aw: Re: Re: no tests for trigonometric functions? need help / hints how to adapt tests for gnumeric 'long' version,
• Date: Sat, 18 Jun 2022 00:05:58 +0200

```
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```- how to deal with / construct tests for functions / ranges where 'long' and 'double' version have
justified different results?
```
```    ( how to build tests which allow / demand improved results, but accept 'double accuracy results' when
using double datatype? )

let me give it an example ( pros will find better ones ):

t1013-crlibm, crlibm.gnumeric, row 18278:

formula:                     '=exp(239.043590469953)'
reference:                   6.536003490281019E+103,
'double' result:             6.536003490281019E+103    - 'quality': ' ' or '99' or 100% or best ...
'long' result:               6.536003490281029007E+103 - 'quality' only 14.819377377076821122 digits, thus
my 'srt-deco-round' version: 6.536003490281095E+103,   - 'quality' only 13.934498683160548 digits, thus
worse? but!!!
correct acc. 'ttmath.org':   6.5360034902810943723150710853138994266057660109196409934141980800730... E103,
and acc. 'wolframalpha.com': 6.5360034902810943723150710853138994266057660109196409934141... × 10^103

thus ttmath and wolframalpha seem correct ( equal ), 6.536003490281094E+103 would be the best approximation
with doubles,
my improved version second, 'long' third and double 'acceptable' ?

idea ... use the correct result as reference, protect against messing it up by saves from low capa versions
by storing as text ( '=value(".... ")' ), prepare for future improved versions by storing more digits (50?),
calculate the 'quality' ( correct digits? ) with the log formula as of now, and require a threshold of e.g
13.9 digits for double and 16.9 digits for long results to pass the test ... ???  one would immediately see
that the long version has far less accuracy ( ~13.99 digits ) than it pretends by it's precision, and could
try to dig for the reason ...

disclaimer: 'no!', I don't really need this level of accuracy, I'm seeking for modes to calculate which don't
undermine math logic, and in this area - tests - I am looking for something that is oriented to normal
mathematics, rewards good results and marks deviations ... for this I also have to play through extreme
considerations ...
```

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