[Maxima-bugs] [ maxima-Bugs-877719 ] integrate and assume

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Bugs item #877719, was opened at 2004-01-15 13:07
Message generated for change (Comment added) made by macrakis
You can respond by visiting: 
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Barton Willis (willisbl)
Assigned to: Nobody/Anonymous (nobody)
Summary: integrate and assume

Initial Comment:
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

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>Comment By: Stavros Macrakis (macrakis)
Date: 2004-01-25 14:14

Message:
Logged In: YES 
user_id=588346

Same bug as 626607.

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