Matt Barber a écrit : > Cyrille, > > Could you try this optimization for the tabread6c~ I threw together? > It uses the same general notation as the tab4c~ suite: > > t_sample a3plusa4plusa5 = 0.25f*c+0.125f*e-0.3333333f*d-0.04166667*a; > t_sample fminusa = f-a; > t_sample eminusb = e-b; > t_sample dminusc = d-c; > > a5 = 0.2083333f*((fminusa-5.f*eminusb+10.f*dminusc)); > a4 = 2.6666667f*eminusb-0.5f*fminusa-5.5f*dminusc-a3plusa4plusa5; > a3 = a3plusa4plusa5-a4-a5; > a2 = 0.6666667f*(d+b)-0.04166667f*(a+e)-1.25f*c; > a1 = 0.6666667f*(d-b)+0.08333333f*(a-e); > a0 = c; > > *out++ = ((((a5 * frac + a4 ) * frac + a3) * frac + a2) * frac + a1) > * frac + a0; > ok
> > I've tested it and I think it works... I count 20 *'s and 25 +'s = 45 > ops vs. 31 *'s, and 27 +'s = 58 ops (if the fractions were written out > as decimals). The compiler should be intelligent enough to convert (2./3.) to 0.666... but using more precision than the 8 digit you write in your code. so i prefer the exact fraction than approximation... cyrille > > Thanks, > > Matt > > >> Date: Tue, 08 Jul 2008 18:35:51 +0200 >> From: cyrille henry <[EMAIL PROTECTED]> >> Subject: Re: [PD] better tabread4~ >> To: Charles Henry <[EMAIL PROTECTED]> >> Cc: [email protected] >> Message-ID: <[EMAIL PROTECTED]> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> hello Chuck, >> >> i tested this. (and commited) >> i think tabread6c~ is a bit better than tabread4c~. but differences are more >> smaller >> >> thx >> >> Cyrille >> >> >> Charles Henry a ?crit : >>> On Sat, Jun 28, 2008 at 6:43 AM, cyrille henry >>> <[EMAIL PROTECTED]> wrote: >>> >>> >>> The coefficients used in this scheme are >>> >>> a0= Y[0] >>> a1= 1/12*Y[-2] - 2/3*Y[-1] + 2/3*Y[1] - 1/12*Y[2] >>> a2= -1/24*Y[-2] + 2/3*Y[-1] - 5/4*Y[0] + 2/3*Y[1] - 1/24*Y[2] >>> a3= -3/8*Y[-2] + 13/8*Y[-1] - 35/12*Y[0] + 11/4*Y[1] - 11/8*Y[2] + 7/24*Y[3] >>> a4= 13/24*Y[-2] - 8/3*Y[-1] + 21/4*Y[0] - 31/6*Y[1] + 61/24*Y[2] - 1/2*Y[3] >>> a5= -5/24*Y[-2] + 25/24*y[-1] - 25/12*Y[0] + 25/12*Y[1] - 25/24*Y[2] + >>> 5/24*Y[3] >>> > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > > _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
