[PD] Vanilla replacement for tanh~

[Miller Puckette]

I've never seen that approximation before but there must be some
restriction on the allowable values of X since the expression diverges
for large positive or negative values of x, while tanh(x) converges to
+1 nad -1, respectively.

cheers
Miller
On Fri, Jul 03, 2015 at 01:23:29PM +0900, i go bananas wrote:
> there's a good approximation for tanh that can be made using just a couple
> of simple arithmetic objects:
> 
> formula is:  tanh(x) ~= x*(27+x*x) / (27+9*x*x)
> 
> it's close enough for every application i've ever come across, it's cheap
> cos it only uses simple arithmetic, and it doesn't degrade the resolution
> of your signal like a table lookup does.
> 
> 
> 
> On Fri, Jul 3, 2015 at 12:56 PM, Chris McCormick <chris at mccormick.cx> wrote:
> 
> > On 03/07/15 03:06, Pagano, Patrick wrote:
> > > Is there a way i can replace something for tanh~
> > > and inits in Vanilla 46?
> >
> > Using a pre-computed table for speed:
> >
> > https://github.com/chr15m/blockhead/blob/master/e_tanh.pd
> > https://github.com/chr15m/blockhead/blob/master/e_tanh-help.pd
> >
> > Or install "blockhead" using deken. :)
> >
> > Cheers,
> >
> > Chris.
> >
> > --
> > http://mccormick.cx/
> >
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