bugGNU Octave - Bugs: bug #57908, complex exponentiation...

 
 

bug #57908: complex exponentiation compatibility issue

Submitted by:  John W. Eaton <jwe>
Submitted on:  Thu 27 Feb 2020 05:48:53 PM UTC
 
Category:  Octave Function Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Matlab Compatibility
Status:  Confirmed Assigned to:  None
Originator Name:  jwe Open/Closed:  * Open
Release:  * dev Operating System:  * Any
* Mandatory Fields

Add a New Comment (Rich Markup)
   

Comment Type & Canned Response:
       

 

Thu 27 Feb 2020 06:34:12 PM UTC, comment #1: 

This is part of a much bigger issue with std::pow().  Interesting that we both came across it at the same time.  See bugs #57671, #57476, #54302, #52706.

Let me write something up for the Octave-Maintainers list (later today or tomorrow).

Rik <rik5>
Project Administrator
Thu 27 Feb 2020 05:48:53 PM UTC, original submission:  

In Octave,

x = complex (0, 0);
x ^ x  => NaN + NaNi
0 ^ 0 => 1

but I believe Matlab the complex exponentiation also returns 1 (or complex (1,0) if narrowing doesn't apply).

Do we need to hunt down and eliminate all uses of std::pow for complex arguments?

Would it be better to eliminate direct use of std::complex and use our own class derived from std::complex and that overloads pow with a function that does what we need for compatibility?

Have we discussed this issue previously?  If so, I didn't find a bug report about it.

John W. Eaton <jwe>
Project Administrator

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:
   
   
Comment:
   

No files currently attached

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -email is unavailable- added by rik5 (Posted a comment)
  • -email is unavailable- added by jwe (Submitted the item)
  •  

    There are 0 votes so far. Votes easily highlight which items people would like to see resolved in priority, independently of the priority of the item set by tracker managers.

    Only project members can vote.

     

     

     

     

    Follows 1 latest change.

    Date Changed by Updated Field Previous Value => Replaced by
    2020-02-27 rik5 StatusNone => Confirmed

    Back to the top


    Powered by Savane 3.9