#332 errors in integrate and factor

closed
nobody
5
2006-04-10
2003-06-25
Anonymous
No

2 6 4 4 6 2 8
432 a y - 504 a y + 6 a y - 3 a
--------------------------------------
2 2 11/2
2 (y + a )
(C26) integrate(%,y,minf,inf);

Type-error in KERNEL::OBJECT-NOT-FIXNUM-ERROR-HANDLER:
NIL is not of type FIXNUM

The same error occured in FACTOR on

sqrt(y^2+a^2)*(432*a^2*y^6-504*a^4*y^4+6*a^6*y^2-3*a^8)/(2*y^12+12*a^2*y^10+30*a^4*y^8+30*a^8*y^2
+12*a^10*y^2+2*a^12)

These errors occured in the following version:

Maxima version: 5.9.0
Maxima build date: 21:17 2/9/2003
host type: i386-redhat-linux-gnu
lisp-implementation-type: CMU Common Lisp
lisp-implementation-version: 18d

Discussion

  • Stavros Macrakis

    Logged In: YES
    user_id=588346

    Please use the linear form of expressions -- this bug reporting
    system loses formatting. I believe the original expression was

    (432*a^2*y^2-504*a^4*y^4+6*a^6*y^2-3*a^9)
    /
    (2 * (y^2 + a^2) ^(11/2) )

    Is that right?

    In 5.9.0/gcl/Windows, I don't get the error you report. ON
    the other hand, Maxima stupidly asks whether y is pos or neg
    (but y only appears as y^2). It does give a result in terms of
    a after a few questions. I have no idea whether this result is
    correct.

     
  • Robert Dodier

    Robert Dodier - 2006-04-10
    • labels: --> Lisp Core - Integration
     
  • Robert Dodier

    Robert Dodier - 2006-04-10

    Logged In: YES
    user_id=501686

    I don't see the " NIL is not of type FIXNUM" errors cited by
    the original poster.

    (1) (432 * a^2 * y^6 - 504 * a^4 * y^4 + 6 * a^6 * y^2 - 3 *
    a^8) / (2*(y^2 + a^2)^(11/2));
    integrate(%,y,minf,inf); => 0 after spurious asksign for y
    and (meaningful) asksign for a.

    From what I can tell, 0 is correct: realroots applied the
    numerator of the above expr yields [y = -36136957/33554432,y
    = 36136957/33554432], and integrating from 0 to
    36136957/33554432 and from 36136957/33554432 to inf shows
    the pieces are equal and opposite. Also quad_qagi (quadpack
    function for infinite interval) seems to show integral is 0
    to within tolerance.

    (By the way, I got the above expression by inspecting the
    HTML page source -- the ascii art layout is comprehensible
    that way.)

    (2) sqrt(y^2+a^2) *
    (432*a^2*y^6-504*a^4*y^4+6*a^6*y^2-3*a^8) /
    (2*y^12+12*a^2*y^10+30*a^4*y^8+30*a^8*y^2 + 12*a^10*y^2+2*a^12);
    factor(%); => pretty much the same expression (no error)

    Works the same with 5.9.1 / CMUCL 19a and 5.9.3 / Clisp 2.34
    (both Linux).

    Closing this report as "works for me" (but I'll open another
    about the spurious asksign for y).

     
  • Robert Dodier

    Robert Dodier - 2006-04-10
    • status: open --> closed
     

Log in to post a comment.

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks