[PD] Vanilla replacement for tanh~

[i go bananas]

yes, you need to use a [clip~ -3 3] to restrict the input.  But the
function converges to +0.999999 and -0.999999 or whatever by then anyway,
so for all practical purposes it is fine.

On Fri, Jul 3, 2015 at 2:26 PM, Miller Puckette <msp at ucsd.edu> wrote:

> 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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