Undefined limit product $INF * $ZEROB in lim-times

[pelegm]

Trying to calculate a limit of some (not too) complicated function brings some kind of console which reports some error/warning. Using algorithm='sympy' is ok, so this is probably a maxima issue.

sage: (x*(4/log(x))^(2*log(x)/log(log(x)))).limit(x=infinity)

Condition of type: SIMPLE-CONDITION
Undefined limit product $INF * $ZEROB in lim-times
Available restarts:

1. (CONTINUE) Return from BREAK.

Top level.
>
0
sage: (x*(4/log(x))^(2*log(x)/log(log(x)))).limit(x=infinity, algorithm='sympy')
0

Tested in SageMath version 8.0.beta5, Release Date: 2017-05-04.

Upstream at https://sourceforge.net/p/maxima/bugs/3313/

Upstream: Reported upstream. No feedback yet.

Component: calculus

Keywords: limit, maxima

Issue created by migration from https://trac.sagemath.org/ticket/23328

[kcrisman]

Description changed:

--- 
+++ 
@@ -1,4 +1,4 @@
-Trying to calculate a limit of some (not too) complicated function brings some kind of console which reports some error/warning.  Using `algorithm=sympy' is ok, so this is probably a `maxima` issue.
+Trying to calculate a limit of some (not too) complicated function brings some kind of console which reports some error/warning.  Using `algorithm=sympy'` is ok, so this is probably a `maxima` issue.
 
 ```python
 sage: (x*(4/log(x))^(2*log(x)/log(log(x)))).limit(x=infinity)

[kcrisman]

comment:2

Huh. Using sage -maxima:

Maxima 5.39.0 http://maxima.sourceforge.net
using Lisp ECL 16.1.2
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) limit((x*(4/log(x))^(2*log(x)/log(log(x)))),x,inf);
(%o1)                                  0
(%i2) domain:complex;
(%o2)                               complex
(%i3) limit((x*(4/log(x))^(2*log(x)/log(log(x)))),x,inf);

Condition of type: SIMPLE-CONDITION
Undefined limit product $INF * $ZEROB in lim-times

Available restarts:

1. (CONTINUE) Return from BREAK.
2. (MACSYMA-QUIT) Maxima top-level

Top level.

So this is an issue in Maxima for sure. Workaround is to set maxima("domain:real"), I guess.

[kcrisman]

Upstream: Reported upstream. No feedback yet.

[kcrisman]

Description changed:

--- 
+++ 
@@ -18,3 +18,5 @@
 
 Tested in SageMath version 8.0.beta5, Release Date: 2017-05-04.
 
+
+Upstream at https://sourceforge.net/p/maxima/bugs/3313/

[pelegm]

Description changed:

--- 
+++ 
@@ -1,4 +1,4 @@
-Trying to calculate a limit of some (not too) complicated function brings some kind of console which reports some error/warning.  Using `algorithm=sympy'` is ok, so this is probably a `maxima` issue.
+Trying to calculate a limit of some (not too) complicated function brings some kind of console which reports some error/warning.  Using `algorithm='sympy'` is ok, so this is probably a `maxima` issue.
 
 ```python
 sage: (x*(4/log(x))^(2*log(x)/log(log(x)))).limit(x=infinity)