Re: Re: with 5.2 Mac
- To: mathgroup at smc.vnet.net
- Subject: [mg59804] Re: [mg59783] Re: with 5.2 Mac
- From: Pratik Desai <pdesai1 at umbc.edu>
- Date: Mon, 22 Aug 2005 02:48:21 -0400 (EDT)
- References: <de6lnl$cfa$1@smc.vnet.net> <200508210751.DAA26532@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Steuard Jensen wrote: >[Reversed order of quotes to make the discussion easier to read:] > > > >>From: Steuard Jensen [mailto:sbjensen at midway.uchicago.edu] To: mathgroup at smc.vnet.net >> >> >>>I've just upgraded from Mathematica 5.0 to 5.2 for the Mac... >>> >>> > > > >>>Specifically, I have used $Assumptions to define some variables as >>>real. I apply Conjugate to various expressions, and then Simplify >>>the results. In version 5.0, I _never_ saw a case in which >>>Conjugate[] remained after this step. But in 5.2, I find that >>>even simple forms like Conjugate[x + I y] often remain >>>unsimplified. (Refine[x + I y] still seems to work, though.) >>> >>> > >Quoth "David Park" <djmp at earthlink.net> in article ><de6lnl$cfa$1 at smc.vnet.net>: > > >>Why don't you use... >> >>ComplexExpand[Conjugate[x + I y]] >>x - I*y >> >>and you don't even have to set $Assumptions? >> >> > >That would be an excellent suggestion for this case, but my actual >work isn't this simple. In particular, my actual expressions include >a mix of complex-valued and real-valued terms. So either I would have >to use $Assumptions as I've done here, or I would have to pass a long >list of complex variables to ComplexExpand each time. (And it's even >possible that my extra TransformationFunctions might replace >combinations of complex variables with real ones, so I might have to >use ComplexExpand more than once.) > >In any case, whether or not ComplexExpand is the _best_ way to do >this, I think that Simplify still ought to work as expected! :) > >Nevertheless, thanks for your suggestion; even if it's not right for >this problem, it could be useful for others. > > Steuard Jensen > > > Here is a somewhat inelegant yet effective approach, instead of using Assumption Use TagSet to define your really "real" variables Clear[a, b, z] TagSet[a, Conjugate[a], a] TagSet[b, Conjugate[b], b] z = a + I*b // Conjugate I use this solution as a last recourse...but it works every time Best Regards Pratik -- Pratik Desai Graduate Student UMBC Department of Mechanical Engineering Phone: 410 455 8134
- References:
- Re: with 5.2 Mac
- From: sbjensen@midway.uchicago.edu (Steuard Jensen)
- Re: with 5.2 Mac