Thanks for picking out the exact expressions that you expected to be the
same. That is what we call a "minimal reproducible report" -- and is much
more helpful than a long script which reports an error at the end. I
actually started looking at your problem but gave up when I realized I'd
have to spend too much time tracking down the issue. Remember, we're all
volunteers here, and happy to help, but....
Here's what seems to be the problem:
It looks like you're assuming that t[0](x) is the same thing as t[0]*(x).
It is not. t[0](x) is the indexed function t with index 0 and argument x.
-s
On Fri, Nov 30, 2012 at 11:11 AM, David Ronis
<ronis at ronispc.chem.mcgill.ca>wrote:
> Hi Richard,
>
> Thanks for the reply. Please see my responses in context below.
>
>
>
> On Fri, 2012-11-30 at 07:20 -0800, Richard Fateman wrote:
> > You say that the form of the exponentials differ.
> >
> > What do the forms look like that you think should be the same?
>
> If I run the sample code I sent (with display2d:false) and look for the
> part beginning with aa[6] I get:
>
> aa[6] = 0
>
> bb[6] = -t[0]*xi^2*D-k[0]^2*t[3]*D-t[0]*Gam
>
> ar = -2*k[0]^2*S(k[0])*K[0](k[0],xi)*Gam*xi^3*D^2
> *%e^(t[0](-xi^2*D-Gam)-k[0]^2*t[3]*D)
> -2*k[0]^4*S(k[0])*K[0](k[0],xi)*Gam*xi*D^2
> *%e^(t[0](-xi^2*D-Gam)-k[0]^2*t[3]*D)...
>
> aa[6] = 0 means that it found nothing multiplying
>
> exp(bb[6])=exp(-t[0]*xi^2*D-k[0]^2*t[3]*D-t[0]*Gam)
>
> ar is the remaining expression (i.e., what I started with less what has
> already been parsed). The 2nd line in ar contains
>
> %e^(t[0](-xi^2*D-Gam)-k[0]^2*t[3]*D)
>
> which would match if the argument were expanded and rearranged.
>
> >
> > Note that radcan does not necessarily choose the same branch of
> > an algebraic function that you might. It also changes exp(a+b)/exp(a).
>
> I'm aware of that, but radcan isn't invoked while parsing the
> expression, and is supposed to give zero. Also, there are no algebraic
> expressions here so the branch isn't relevant.
>
> > So far as I can tell, none of the "assume" commands should affect
> > anything you are doing.
>
> You're probably correct, but there were needed in the real problem and I
> wanted to make sure that the environment used for ordering the
> expressions was the same.
>
> >
> >
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