The bignumber package in maxima is in one file (float.lisp) probably.
It is not especially fast because it attempts to do rounding
correctly to the last bit as prescribed by the IEEE floating point
rules. If you can manage with simpler rules, the code will probably
be twice as fast. (A change to fptrunc will do this).
If you want fast VERY BIG bigfloats, then a linkage to GMP or perhaps
ARPREC should be considered. This is what I have done from
Allegro common lisp, and I assume that CMUCL has similar foreign
function capabilities, if not identical declaration syntax.
If you want double-double precision (2Xdouble), or
4Xdouble then there are
routines available for this that are quite fast. David Bailey
has pointers to these at
http://crd.lbl.gov/~dhbailey/mpdist/
Regarding PDEs -- there is (was?) a package called
PDEase sold with commercial Macsyma. The documentation
might be of help, even if the code is unavailable. On the
other hand, I don't solve PDEs for a living and can't
evaluate the design myself. I suspect it is OK for
teaching. It also may not have much to do with
symbolic computation.
Best of luck
RJF
Nicolas Neuss wrote:
>Richard Fateman <fateman@cs.berkeley.edu> writes:
>
>
>
>>Depending on how much polynomial manipulation you
>>need, you may find other simpler things to do, perhaps
>>taking a few pages of lisp. For example, you probably
>>don't need to worry about GCD computations, or polynomials
>>of high degree. Representing polynomials in n variables
>>as n-dimensional arrays may be entirely adequate, especially
>>since the polynomial stuff would be done (I imagine) only
>>in setting up the problem, not in the iterations.
>>RJF
>>
>>
>
>What I would need most is multiprecision floating point numbers. Do you
>know a separate package for this? (I know CLISP has this, but CLISP does
>not do native code compilation and is therefore not suited for hardcore
>numerics. And I need it sometimes also out of the initialization phase,
>e.g. for postprocessing. Imagine wanting to evaluate a finite element
>function on some arbitrary point in the domain).
>
>In the (very?) far future, I could imagine benefits for using other parts
>of Maxima as well. Especially, I'm thinking of extending the Maxima
>language to handle also partial differential equations (e.g. enter
>coefficient functions in a mathematical form, call solve, plot the
>solution).
>
>Nicolas.
>
>_______________________________________________
>Maxima mailing list
>Maxima@www.math.utexas.edu
>http://www.math.utexas.edu/mailman/listinfo/maxima
>
>