Re: Compiled function slowdown

*To*: mathgroup at smc.vnet.net*Subject*: [mg86723] Re: [mg86682] Compiled function slowdown*From*: DrMajorBob <drmajorbob at bigfoot.com>*Date*: Wed, 19 Mar 2008 05:26:35 -0500 (EST)*References*: <9949215.1205837642926.JavaMail.root@m08>*Reply-to*: drmajorbob at longhorns.com

Send the e1, e2, and fComp functions, and I'll be curious to untangle this mess. Without them, it's incomprehensible. Bobby On Tue, 18 Mar 2008 04:50:04 -0500, mm1q <epv001 at lvc.edu> wrote: > Hello, > > In a program I'm currently working on, I need to loop through a function > ~100,000 times. I thought I'd try compiling it to save on time. > However, it takes more than 10 times longer to run than the uncompiled > (module) version. Are there any general guidelines as to when a > compiled function will be slower than its uncompiled counterpart in > Mathematica (such as with the use of many conditional statements)? I've > included my function below (sorry if it's a mess; e1, e2 and fComp are > very simple compiled functions), though a general response to the above > question would be just fine. Thanks! > > generator = Compile[{stepTotAccum_Real, {dxTable, _Real, 1}, > pTile_Real, area_Real}, > Do[ > While[True, > u = Random[]; > If[ u < stepTotAccum, > stats = 1 + 4*Floor[u/pTile]; > cand = (u - dxTable[[stats + 2]])/dxTable[[stats + 1]]+ > dxTable[[stats]]; > If[Random[]*dxTable[[stats + 3]] < fComp[cand], > Return[cand * (-1)^Random[Integer]] > ]; > , > cand = e1[u]; > If[e2[Random[], cand, area] < fComp[cand], > Return[cand * (-1)^Random[Integer]] > ]; > ]; > ]; > ] > ]; > > -- DrMajorBob at longhorns.com