#321 limit overflows memory?

closed
nobody
5
2007-10-23
2003-05-28
Stavros Macrakis
No

expr: (x^(1/n)+1)^n/2^n;

limit(expr,n,inf);
Is x positive or negative?

pos;Is x - 1 positive or negative?

pos;
Error: Contiguous blocks exhausted.
Currently, 129 pages are allocated.
Use ALLOCATE-CONTIGUOUS-PAGES to expand
the space.
Fast links are on: do (si::use-fast-links nil) for debugging
Error signalled by MACSYMA-TOP-LEVEL.
Broken at HAIPART. Type :H for Help.

--------------------------

a) Of course it shouldn't cause this sort of error at all.

b) What is allocate-contiguous-pages??? There is
apparently no such function in gcl.

By the way, tlimit gets the correct result, sqrt(x).

Maxima 5.9.0 GCL 2.5.0 mingw32 Windows 2000 Athlon

Discussion

  • Raymond Toy
    Raymond Toy
    2003-05-28

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    user_id=28849

    With CMUCL, we also get an error. It seems we're trying to
    compute 2^16384, and CMUCL stops if the exponent is too
    large. Presumably gcl is trying to compute the same thing
    and has run out of memory for this number.

     
  • Robert Dodier
    Robert Dodier
    2006-04-09

    • labels: --> Lisp Core - Limit
     
  • Robert Dodier
    Robert Dodier
    2006-07-07

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    user_id=501686

    Still present in 5.9.3cvs / sbcl 0.9.9. In this case the
    error is "The value 536870912 is not of type FIXNUM".

     
  • Dan Gildea
    Dan Gildea
    2007-10-23

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    user_id=1797506
    Originator: NO

    works in current cvs.

    (%i5) assume(x>1);
    (%o5) [x > 1]

    (%i6) expr: (x^(1/n)+1)^n/2^n;
    (%o6) (x^(1/n)+1)^n/2^n

    (%i7) limit(expr,n,inf);
    (%o7) sqrt(x)

     
  • Dan Gildea
    Dan Gildea
    2007-10-23

    • status: open --> closed