Logarithms.

[Cookiemaster]

Is there any way to use logarithms in Warcraft 3? (E.G. 10log(TEMP_REAL[1])=?)

 

[Flare]

By default? Don't think so

AFAIK, Vexorian wrote some logarithm functions, you can check them out in the Code Resources -> Scripts (I think it's the scripts sub-section) over at WC3Campaigns

 

[Exide]

I'm not sure.
Maybe there's another way to achieve what you want, though. What are you trying to do?

 

[Larcenist]

There are no functions in the WE as far as I know that utilizes logarithms, though why would you need it in the first place?

 

[Jooster]

i believe you are able to "make" your own. blizzard did seat us well with a decent mathematical system. I'm just curious as to how u would implement the logarithm system into.

 

[Cookiemaster]

I'm making a damage system, but I want to display the damage on the unit relatively. (1 damage = velocity angle 300', 10 velocity angle 0', 100 velocity angle 60', etc.)

 

[Jooster]

i would of had guess armor or a income system, mostly constants. honestly i dont think u are going to be able to make something like that without a very long complicated code :<

 

[Flare]

Vexorian's logarithm function(s)
BlinkBoy's natural logarithm function(s)

 

[AceHart]

Well, I'd go with this "approximation":

If damage greater than 1000 then
- Set angle =
else if damage greater than 100 then
- Set angle =
else if damage greater than 10 then
- Set angle =
else
- Set angle =

It's not as accurate as an actual log function, but it certainly beats them all when it comes to speed.


Just for the fun of it:

function log takes real x returns real
    if x <= 0 then
        return 0.0
    endif
    set x = x - 1.0
    return x / (1 + x / (2 + x / (3 + 4 * x / (4 + 4 * x / (5 + 9 * x / (6 + 9 * x / (7 + 16 * x / (8 + 16 * x  / (9 + 25 * x / (10 + 25 * x / (11 + 36 * x / (12 + 36 * x / (13 + 49 * x / (14 + 49 * x / (15 + 64 * x / (16 + 64 * x / (17 + 81 * x / (18 + 81 * x / (19 + 100 * x / (20 + 100 * x))))))))))))))))))))
endfunction

Not overly precise on large values but "good enough" for most uses. Fast too since it doesn't use any loops...

 

[Uberplayer]

return x / (1 + x / (2 + x / (3 + 4 * x / (4 + 4 * x / (5 + 9 * x / (6 + 9 * x / (7 + 16 * x / (8 + 16 * x  / (9 + 25 * x / (10 + 25 * x / (11 + 36 * x / (12 + 36 * x / (13 + 49 * x / (14 + 49 * x / (15 + 64 * x / (16 + 64 * x / (17 + 81 * x / (18 + 81 * x / (19 + 100 * x / (20 + 100 * x))))))))))))))))))))

That doesn't look too fast with all those divisions and everything.

[DEL]And when x is 1.0, it becomes 0.0 (x = x - 1.0), and then you get divided by 0 error.[/DEL]
(forget it)

 

[AceHart]

Have a look at the others.
See those loops?
See what they do inside?
This does it all in one go, without looping.

The only known problem is the lack of precision on higher values.
Well, that and the general usefulness of a log function...

It's base e by the way.
To get other bases:

Log(b) X = Log(e) X / Log(e) b
I.e. the log of X in base b equals log X divided by log b in some known base.
The divisor can be pre-calculated of course.

Personally, I'd still go with the somewhat rough but foolproof approximation...

 

[Trollvottel]

http://hilton.gw.oiccam.com/showthread.php?p=1050479#post1050479

a few logarithm functions...and benchmarking

 

[Light Alkmst]

If you want, I could use newly learned series stuff (Taylor polynomials) to help find a formula if AceHart's isn't sufficient...would take a good deal of time though...