Entre otras cosas, Jano tuvo a bien escribir:

> If i do (i.e.) y= cos(x) where 0 < x < 2*pi and i'm testing the following:
>    #if(y < 0)
>       //block1...
>    #else //block2...
> 
> the result when x= pi*3/2 is block1! And taking a look at its value, is
> -0.00000 and is taken as negative number. By now i correct it simplyly
> checking such y value:  #macro correct(num)(num<0?:num=0?0:num:num) #end
> 
> Can someone confirm if this is a bug? Thanks

What would you expect?

cos(0) = 1
cos(pi*1/2) = 0
cos(pi) = -1
cos(pi*3/2) = 0

Unfortunately, POV-Ray is not perfect and there are (as in most computer 
programs) floatin point inaccuracies and rounding errors. That means the 
result is not *exactly* 0, but slightly lower, and you see -0.000. This is 
normal and expected behaviour, if you are testing against 0 you should in 
turn test that abs(y) < tiny_number.

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Linux User #289967 (counter.li.org)
PGP Pub Key ID: 0x01A95F99 (pgp.escomplinux.org)

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