On Mon, Apr 21, 2008 at 1:28 PM, Richard Hennessy <rvh2007 at comcast.net>
wrote:
> I just want to be able to diff it with respect to y. Is this too much to
> ask?
>
Why the exasperated tone? Maxima easily does this, though the result and the
coefficients are large. Just use rat form for reasonable runtime.
f(rat(x),rat(y))$
Evaluation took 2.17 seconds (2.17 elapsed)
diff(%,y)$
Evaluation took 2.61 seconds (2.61 elapsed)
Displaying the results in a reasonable way might be trickier, since this is
an expanded polynomial of 15000+ terms, with many of the coefficients > 1000
digits (e.g. 326 digit numerator, 738 digit denominator).
ratcoef(ratcoef(sr,x,250),y,49);
Evaluation took 1.54 seconds (1.54 elapsed)
=> 4316..(166 more digits)..1583 / 9660..(403 more digits)..0000
i.e. the term is
4316..(166 more digits)..1583 / 9660..(403 more digits)..0000 * x^250 * y^49
display2d:false might be your best bet for simple printout.
What exactly is the next step in your processing of terms like this?
Instead of printing them out, perhaps you should continue processing with
Maxima somehow? Of course, if it's good enough to truncate to N decimal
digits, you can also use fpprec:N and convert to bfloats.
-s