log to the base x
how to i do log to the base x in max?
jimdrake wrote on Wed, 10 June 2009 14:20how to i do log to the base x in max?
have you tried typing "log" into an object box yet?
newobj: log: No such object
Look at the [expr] object and reference. There's a log10 function and a log (natural log) function. The syntax is standard C, so any C reference will point you in the right direction if you can't figure it out by trial and error.
i hunted around and i can't see anything in C that lets you do log to the base x.
i did however dig out a text book from uni (!) and found this useful rule:
logA(x) = logB(x) / logB (a)
[capitals are meant to be subscript]
so, i can do it in [expr] with log to the base 10
jimdrake wrote on Wed, 10 June 2009 16:09i hunted around and i can't see anything in C that lets you do log to the base x.
i did however dig out a text book from uni (!) and found this useful rule:
logA(x) = logB(x) / logB (a)
[capitals are meant to be subscript]
so, i can do it in [expr] with log to the base 10
[expr log(($f1)*($f2-1)+1)/log($f2)]
this is for a range of 0. 1.
for other ranges just scale before and after.
frustrating, that expierience when typing "log" into an
object box, isnt it?
-110
...and if you want to include the input range into the
formula, you might end up with something like this:
[expr ((log((($f1-$f2)/($f3-$f2))*($f4-1)+1)/log($f4))*($f3-$f2))+$f2]
where $f2 $f3 are range low range high, and $f4 is the base.