[PD] problem: expr~ divide by zero detected

federico xaero at inwind.it
Sun Sep 4 14:17:54 CEST 2005

federico ha scritto:

> main problem: i want to control an osc~ by a logaritmic curve.
> i use a vline~ to track the linear line, and an expr~ to wrap into a 
> log(..) curve.
> the problem is that expr~ complains about a division by zero.
> i inserted a number to check if is it true... and in the fact the 
> "dividendo" is not zero.
> how can i solve this problem? (the problem of: having a 
> linear/logarithmic/exponential vline~ object)
> many thanks
i forgot to attach the example patch: SFX~.pd

the formula I tested in gnuplot is:
gnuplot> plot [0:1] log(x*10.93+1)/log(10.93+1)

where 10.93 could be a value >0 and it controls the amount of curve.
in the patch i replaced the last part ("log($v2+1)") with "$v3" just to
check its value it was not zero.

if you disconnect [expr~ ....] from [osc~], and connect the first
[vline~] to [osc~] you get the traditional behavior, with linear
interpolated points.

how do you solve this problem in the signal domain? lop~?
how does lop~ react to quick changes of cutoff frequency?


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