Re: Calling functions with huge arguments

*To*: mathgroup at smc.vnet.net*Subject*: [mg97681] Re: Calling functions with huge arguments*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 18 Mar 2009 04:57:17 -0500 (EST)*Organization*: Uni Leipzig*References*: <gpns8b$gkh$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, the best way is to make a block in your top-level function as in thr example below ToplevelFunction[huge_]:=Block[{hugeLocalCopy=huge}, nextlevel[]; ] nextlevel[]:=Module[{any=2},hugeLocalCopy=any*hugeLocalCopy] Block[] mak a dynamic scoping, i.e., all functions called from a Block[] can access its local data. Regards Jens Fernando Cucchietti wrote: > Hi all, > > I am working with a VERY large tensor, so much that I would like to > keep at most two copies of it in memory at any given time. The > algorithm I want to run is convoluted and repetitive, but it looks > very compact when written in terms of subroutines and functions that > call themselves many times. However, from what I gather, Mathematica > effectively creates a copy of the arguments when a function is called. > Is this correct? > If so, I need to find a way to mimic pass-by-reference style as in C > or Fortran, or just pass the arguments that are not big and keep my > tensors defined globally (which I think makes the code look less > nice). Unwrapping the code so that it does not call functions is not > an option, because it would be very complex and never-again-usable. > My main question is then: what are the best ways to do pass-by- > reference (if it is better than global naming), or what approaches > have you taken to overcome similar problems? > > Thanks in advance, > > Fernando >