Log

[Matthias Kretz]

Hi Igor,

On Tuesday 28 May 2013 09:09:09 Kulakov, Igor wrote:
> It looks ok in release mode, but in debug I get:
> 
> Assertion failed: ((*this >= 0.f).isFull()), function exponent, file
> /usr/local/include/Vc/sse/vector.tcc, line 1337.
> 
> It appears when log(-1) is taken.

Yes, that's a bug.

> Do you have an idea what can be the problem? log(-1) == NAN isn't it?
> Do I use log incorectly?

Yes, log(-1) should give you NAN in release mode, no? The issue is that the 
implementation of log uses another function in Vc (Vector::exponent()) which 
does not handle negative numbers.

This probably needs a refactoring: move everything but the assertion of 
exponent() into a new function that gets called by log and exponent...

If you don't want to do a complete fix, then just delete the assertion.

Cheers,
	Matthias

-- 
Dipl.-Phys. Matthias Kretz

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