#490 integrate and assume

closed
nobody
Lisp Core (471)
5
2005-08-22
2004-01-15
No

This is okay:

(C1) integrate(exp(a*x),x,0,inf);
Is a positive, negative, or zero? pos;
Integral is divergent

The assumption on "a" is local --

(C2) is(a > 0);
MACSYMA was unable to evaluate the predicate:

But integrate remembers the assumption on "a."
I think this is a bad feature:

(C3) integrate(exp(a*x),x,0,inf);
Integral is divergent

Wait! Look what happends if we trace ?assume. It
seems that integrate forgets the assumption
on "a" and once again asks for the sign of "a."

(C4) trace(?assume)$
(C5) integrate(exp(a*x),x,0,inf);
1 Enter ?ASSUME [*Z* > 0]
1 Exit ?ASSUME *Z* > 0
... (stuff deleted)

Is a positive, negative, or zero?
neg;

1 Enter ?ASSUME [x > 0]
1 Exit ?ASSUME x > 0
1 Enter ?ASSUME [x > 0]
1 Exit ?ASSUME x > 0
1 Enter ?ASSUME [INF > x]

...(stuff deleted)

(D5) -1/a

Is this a bug with gcl's trace?

(C8) build_info();

Maxima version: 5.9.0
Maxima build date: 19:10 2/9/2003
host type: i686-pc-mingw32
lisp-implementation-type: Kyoto Common Lisp
lisp-implementation-version: GCL-2-5.0

Barton

Discussion

  • Stavros Macrakis

    Logged In: YES
    user_id=588346

    Same bug as 626607.

     
  • Robert Dodier

    Robert Dodier - 2005-08-22

    Logged In: YES
    user_id=501686

    Closing this bug report as a duplicate of 626607 (as noted
    below). No need to have both reports open.

     
  • Robert Dodier

    Robert Dodier - 2005-08-22
    • status: open --> closed
    • labels: --> Lisp Core
     

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