Subject: denominator of really complicated expression
From: Richard Fateman
Date: Mon, 21 Nov 2005 18:59:39 -0800
put at the front:
showtime:all$
ratmx:true$
nolabels:true$
abeam:rat(abeam)$
ratvars(abeam, cbeam, .....) ... list all the variables
...
ratdenom(bode0);
exclude computing stuff you don't need to compute bode0.
don't use expand. all values including abeam will be expanded
automatically, and the denominator
change all the ; to $
Ryan Krauss wrote:
> I have a really complicated expression I need to find the denominator
> of. When I save the expression to file the file is 300kb. The
> expression has some smaller fractions sprinkled though out, so I need
> to expand it before I can call denom. (denom on the un-expanded
> expression just gives 1). When I call either expand or radcan on the
> expression, it runs for several minutes, maxima takes up 300-400 megs
> of memory and then stops with the message:
> (%i104) bob:expand(bode0);
>
> Maxima encountered a Lisp error:
>
> Error in CATCH [or a callee]: The storage for CONS is exhausted.
> Currently, 66689 pages are allocated.
> Use ALLOCATE to expand the space.
>
> Automatically continuing.
> To reenable the Lisp debugger set *debugger-hook* to nil.
> (%i105)
>
> Does anyone have any suggestions for expanding or finding the
> denominator of a really long expression in a way that doesn't have
> this error?
>
> The attached batch file generates the expression. The expression I
> need to simplify is called bode0.
>
> Thanks,
>
> Ryan