Yes, I wrote the poisson stuff.
As I recall, there are two different encoding schemes used for the
coefficients, one more efficient (but restricted to CRE) than the other,
which uses the general simplify "SIMPLIFYA" program.
Sort of like RATMX.
It was intended that only ONE of the two poisson series packages be loaded.
Someone (Perhaps Bill Schelter?) seemed to set up the system so that
they both were loaded.
But then someone (else?) decided to comment out all the code in one of
them, pois2.
The version that is left, pois3, does not use CRE..
Consequently, the code in ratpoi, which uses CRE, is overwritten and is
never used.
There are other options for poisson series that have to do with how the
trig arguments are encoded, related to $poislim.
Why all this fuss about apparent low-level hacks, and TWO versions of
the same code, one of which should be used at runtime?
Poisson series is one of the few areas in which efficiency is SO
important that apparently minor hacks make or break the feasibility of
computations. You don't want more generality than you absolutely need.
Or at least that was the case when this code was written, circa 1971.
Since no one seems to use the poisson stuff in maxima, it probably does
not matter that it is broken, and the documentation written by someone
who didn't understand it.
I think the corresponding code works in Macsyma.
Andreas Eder wrote:
>Hello,
>
>I just discovered that all function definitions in ratpoi.lisp are
>redefined in a different way in pois3.lisp.
>Does anyone know the reason behind this?
>Just for testing purposes I commented out everything in
>ratpoi.lisp and everything still seems to work. The testsuite
>doesn't give me any errors, but there aren't that many tests in it
>that call functions in pois3.
>Could anyone comment on the situation? It seems pretty strange to
>me.
>
>'Andreas
>
>--
>Wherever I lay my .emacs, there's my $HOME.
>_______________________________________________
>Maxima mailing list
>Maxima at math.utexas.edu
>http://www.math.utexas.edu/mailman/listinfo/maxima
>
>