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description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: Re: Numerical Recipes diffs?

Re: Numerical Recipes diffs?
type: item
description: kachun@bogart.Colorado.EDU (Ka Chun Yu) writes: > I've now tested the IDL3 and IDL4 equivalents of the above routines > with the same inputs, and both routines give different results in > the two IDL versions. One possible reason for the different results is that the new routines take row-major arrays, not column-major. (I might have just switched these two -- anyway, the new routines take the transpose of the old format.) All the differences are described in the on-line help. Kevin ----------------------------------------------------------- Kevin Spencer Cognitive Psychophysiology Laboratory and Beckman Institute University of Illinois at Urbana-Champaign kspence1@uiuc.edu -----------------------------------------------------------
creator: kspencer
date: 1996-06-20T07:00:00-00:00

Re: Numerical Recipes diffs?
type: item
description: In article <4qbh8u$r9b@fu-berlin.de> marq@strat01.met.fu-berlin.de writes: > Ka Chun Yu (kachun@bogart.Colorado.EDU) wrote: > : Does anyone know what IDL did between IDL3 and IDL4 as far as > : the numerical recipes subroutines go? I've been testing a fitting > : program that uses the LUDCMP and LUBKSB routines form _Numerical > : Recipes_, and I've been using IDL's canned routines. The canned > : routines got name changes during the switch from IDL3 to IDL4, > : from "nr_ludcmp" and "nr_lubksb" to "ludc" and "lusol". That's > : not all though--somehow the code got changed around so that I > : get different results depending on which version of IDL I use > : even if the input is exactly the same! > Check the link 'What was New in IDL version 4.0' / Mathematics Improvements' > of the IDL Online Help (idlhelp, or ? from the IDL command prompt). > Probably the most important sentence: > > "Note that the old routine names still work, but are undocumented." Yes I noticed this. Unfortunately this statement does not seem to hold for LUDCMP and LUBKSB. Running "nr_ludcmp" or "nr_lubksb" gives me a "Variable is undefined:" error in IDL4. I've now tested the IDL3 and IDL4 equivalents of the above routines with the same inputs, and both routines give different results in the two IDL versions. > Chris Marquardt (marq@strat01.met.fu-berlin.de) -- --kachun +** Center for Astrophysics and Space Astronomy **+ +** University of Colorado, Boulder **+ +** Email: kachun@casa.colorado.edu **+ +** http://casa.colorado.edu/~kachun **+
creator: kachun
date: 1996-06-20T07:00:00-00:00

Re: Numerical Recipes diffs?
type: item
description: Ka Chun Yu (kachun@bogart.Colorado.EDU) wrote: : Does anyone know what IDL did between IDL3 and IDL4 as far as : the numerical recipes subroutines go? I've been testing a fitting : program that uses the LUDCMP and LUBKSB routines form _Numerical : Recipes_, and I've been using IDL's canned routines. The canned : routines got name changes during the switch from IDL3 to IDL4, : from "nr_ludcmp" and "nr_lubksb" to "ludc" and "lusol". That's : not all though--somehow the code got changed around so that I : get different results depending on which version of IDL I use : even if the input is exactly the same! : I don't think IDL provides the source for these routines in their : libraries; they leave them as executables. So does anyone know : what IDL did between versions, or should I just forget about this : and rewrite everything from scratch (which would be really annoying)? Check the link 'What was New in IDL version 4.0' / Mathematics Improvements' of the IDL Online Help (idlhelp, or ? from the IDL command prompt). Probably the most important sentence: "Note that the old routine names still work, but are undocumented." Hope this helps, Chris Marquardt (marq@strat01.met.fu-berlin.de)
creator: marq
date: 1996-06-20T07:00:00-00:00

Re: Numerical Recipes diffs?
type: item
description: In article <4qchu0$2qc@vixen.cso.uiuc.edu> kspencer@s.psych.uiuc.edu (Kevin Spencer) writes: > kachun@bogart.Colorado.EDU (Ka Chun Yu) writes: > >> I've now tested the IDL3 and IDL4 equivalents of the above routines >> with the same inputs, and both routines give different results in >> the two IDL versions. > > One possible reason for the different results is that the new routines > take row-major arrays, not column-major. (I might have just switched > these two -- anyway, the new routines take the transpose of the old > format.) All the differences are described in the on-line help. Yes! That was the problem. One could either enter in the transpose of the input matrixes, or for some functions, specify the COLUMN key- word to use column-major input. Thanks to all those who helped. > Kevin -- --kachun +** Center for Astrophysics and Space Astronomy **+ +** University of Colorado, Boulder **+ +** Email: kachun@casa.colorado.edu **+ +** http://casa.colorado.edu/~kachun **+
creator: kachun
date: 1996-06-21T07:00:00-00:00