Re: Simplifying Conjugate[] with 5.2 Mac
- To: mathgroup at smc.vnet.net
- Subject: [mg59773] Re: Simplifying Conjugate[] with 5.2 Mac
- From: "James Gilmore" <james.gilmore at yale.edu>
- Date: Sat, 20 Aug 2005 03:14:36 -0400 (EDT)
- Organization: Yale University
- References: <de45i8$qtf$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
> In[5]:= Simplify[Conjugate[x+I y]]
>
> Out[5]= Conjugate[x + I y]
With regard to this behaviour, it may be useful to use PlusMap (or Map if
there are always at least two terms when expanded), see FurtherExamples, in
the Map documentation.
$Assumptions = {{a, b} \[Element] Reals};
PlusMap[f_, expr_ /; Head[expr] =!= Plus, ___] := f[expr];
PlusMap[f_, expr_Plus, r___] := Map[f, expr, r];
Trace[Simplify[PlusMap[Conjugate, Expand[a + I*b]]]]
Trace[Simplify[PlusMap[Conjugate, Expand[a + b]]]]
--
James Gilmore
Graduate Student
Department of Physics
Yale University
New Haven, CT 06520 USA
"Steuard Jensen" <sbjensen at midway.uchicago.edu> wrote in message
news:de45i8$qtf$1 at smc.vnet.net...
> I've just upgraded from Mathematica 5.0 to 5.2 for the Mac, and I
> discovered that a notebook that ran fine before (finishing in ten or
> fifteen minutes) was now being tremendously slow. I'm sure I haven't
> tracked down everything that I need to fix by hand to speed it back up
> again (I did a lot of tuning when I wrote it), but it seems that part
> of the problem can be tracked back to what looks like a bug in
> Simplify[] (or at least an awfully annoying behavior).
>
> 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.)
>
> I've cut and pasted a simple example below, and I'd be interested to
> know if other people experience the same behavior. I'd appreciate any
> advice or comments on how to handle this, or on where I should write
> to report this strange behavior to Wolfram if you think that's
> appropriate. Thanks in advance for any help you can give.
>
> Steuard Jensen
>
> ------------------------------------------------------------
>
> In[1]:= $Assumptions={Element[{x,y},Reals]};
>
> In[2]:= Simplify[Conjugate[x]]
>
> Out[2]= x
>
> In[3]:= Simplify[Conjugate[I y]]
>
> Out[3]= -I y
>
> In[4]:= Simplify[Conjugate[x+y]]
>
> Out[4]= x+y
>
> In[5]:= Simplify[Conjugate[x+I y]]
>
> Out[5]= Conjugate[x + I y]
>
> In[6]:= Refine[Conjugate[x+I y]]
>
> Out[6]= x - I y
>
> ------------------------------------------------------------
>