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#2751 powerseries of bessel functions needlessly fail

None
closed
nobody
None
5
2014-06-22
2014-06-07
Barton Willis
No

I'm not sure, but I think that sratp (defined in series.lisp) is supposed to test for
a rational function. But it returns true for some nonrational functions and that causes
some power series to needlessly fail:

(%i2) powerseries(bessel_j(0,x),x,0);
1> (SRATP ((%BESSEL_J SIMP) 0 $X) $X)
<1 (SRATP T)
(%o2) "Failed to expand"

I'm not sure what smono (defined in asum.lisp) does, but possibly the final
(t (free (cadr a) var))) clause in sratp is defective.

Discussion

  • Barton Willis
    Barton Willis
    2014-06-22

    The series for the Bessel functions should be improved, but the error is eliminated
    by Commit:bf243f836a6b50598b12b28f46d366168ceedd97

     
  • Barton Willis
    Barton Willis
    2014-06-22

    • status: open --> closed