Re: Is there a faster way?

*To*: mathgroup at smc.vnet.net*Subject*: [mg30593] Re: [mg30552] Is there a faster way?*From*: Tomas Garza <tgarza01 at prodigy.net.mx>*Date*: Thu, 30 Aug 2001 03:51:42 -0400 (EDT)*References*: <200108290539.BAA04898@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Looks like a big problem. It would be interesting to know where you find the slowness: is it in the importing operation, or in the actual calculation? I guess it is in the import, in which case you might rearrange your data so as to have a single (or just a few) importing process, even if that leaves you with a huge array to work with. Another possibility (and I'm just talking through my hat) would be to have your files in Mathematica format previously Put (>>) there, so that instead of using Import you use Get (<<), which is much faster. Unless, of course, these files have to be externally changed often, in which case I don't know what can be done.... Tomas Garza Mexico City ----- Original Message ----- From: <Moranresearch at aol.com> To: mathgroup at smc.vnet.net Subject: [mg30593] [mg30552] Is there a faster way? > > I have a large list of 40,000 file names = f1, each file name corresponds to > a 360 x 19 matrix of real numbers,I need to run the calculation on each file > and save the answer in a list of results. The method below works but is slow, > is there a better way? Thank you. John R Moran PhD, MD. > > Table[Map[ > StandardDeviation, {Table[.01* > StandardDeviation[ > Column[Partition[Drop[Import[f1[[j]], "List"], 1], 19], i]] // > N, {i, 2, 11}]}], {j, 1, Length[f1]}] > >

**References**:**Is there a faster way?***From:*Moranresearch@aol.com