Re: Do-loop conversion
- To: mathgroup at smc.vnet.net
- Subject: [mg50283] Re: [mg50211] Do-loop conversion
- From: "David Annetts" <davidannetts at ihug.com.au>
- Date: Tue, 24 Aug 2004 06:22:30 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Rich,
<snippage>
Do[
wavevectmap := wavetabc[revdelta, revbeta, phi];
leftvectmap := leftvectmapc[wavevectmap];
thtest := thtestcomp[revrough, leftvectmap, wavevectmap];
maproughrev := roughrevcomp[thtest];
coeffmap := coeffcomp[wavevectmap, leftvectmap, maproughrev];
phasemap := phasecomp[wavevectmap, revthick];
coeffs := fcoeffcomp[coeffmap, phasemap];
recurr[prior_, {fc_, pf_}] := (fc + (prior*pf^2))/(1 +
(fc*prior*pf^2));
intensity := intensitycomp[Fold[recurr, 0, coeffs ]];
newdata = newdatacomp[phi, intensity, params];
newc = AppendTo[newc, newdata],
{phi, phistart, phiend, phiinc}]
<snippage>
-------------------
An easy(!) way into a functional style might be ...
1. define phirange = Range[phistart, phiend, phiinc];
2. map this range using
newc = (
wavevectmap := wavetabc[revdelta, revbeta, #];
leftvectmap := leftvectmapc[wavevectmap];
thtest := thtestcomp[revrough, leftvectmap, wavevectmap];
maproughrev := roughrevcomp[thtest];
coeffmap := coeffcomp[wavevectmap, leftvectmap, maproughrev];
phasemap := phasecomp[wavevectmap, revthick];
coeffs := fcoeffcomp[coeffmap, phasemap];
recurr[prior_, {fc_, pf_}] := (fc + (prior*pf^2))/(1 +
(fc*prior*pf^2));
intensity := intensitycomp[Fold[recurr, 0, coeffs ]];
newdata = newdatacomp[#, intensity, params];
)& /@ phirange
Another speed improvement might be to precompute wavevectmap and using it as
a table lookup; from your code excerpt, there's no need to have this inside
the loop.
Regards,
Dave.