#912 Maxima thinks pochhammer is real

closed
Barton Willis
3
2007-11-19
2006-04-30
Barton Willis
No

(%i1) load("orthopoly")$
(%i2) pochhammer(1+%i*2,n);
(%o2) pochhammer(2*%i+1,n)

(%i3) imagpart(%);
(%o3) 0 <--- Bogus!

Also, conjugate should commute with pochhammer, but it
doesn't:

(%i4) conjugate(%o2);
(%o4) conjugate(pochhammer(2*%i+1,n))

Finally, the simplification

(%i5) pochhammer(x,-n);
(%o5) 1/((-1)^n*pochhammer(1-x,n))

is not wrong, but goofy. (I think this simplification
should only happen when n is an positive integer -- not
declared to be an integer or assumed positive.)

I have fixes for all these things that I'll submit
after testing. My fixes will convert pochhammer to
a simplifying function.

Barton

Discussion

  • Robert Dodier
    Robert Dodier
    2006-08-24

    Logged In: YES
    user_id=501686

    Results observed in 5.9.3.99rc2 / SBCL 0.9.9 / Linux:

    pochhammer(1+%i*2,n);
    imagpart(%);
    => 0 (STILL BOGUS)

    conjugate(pochhammer(1+%i*2,n));
    => pochhammer(1-2*%i,n) (SEEMS OK)

    pochhammer(x,-n);
    => 1/((-1)^n*pochhammer(1-x,n)) (SAME AS BEFORE)

     
  • Barton Willis
    Barton Willis
    2007-11-19

    Logged In: YES
    user_id=895922
    Originator: YES

    fixed in CVS orthopoly version 1.7

     
  • Barton Willis
    Barton Willis
    2007-11-19

    • status: open --> closed