bugGNU Octave - Bugs: bug #43311, symbolic: Wrong expected value in...

 
 

bug #43311: symbolic: Wrong expected value in symfsolve test

Submitted by:  Rafael Laboissiere <rlaboiss>
Submitted on:  Sun 28 Sep 2014 12:07:32 AM UTC  
 
Category:  Octave Forge Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Wont Fix Assigned to:  None
Originator Name:  Open/Closed:  Closed
Release:  dev Operating System:  GNU/Linux

Add a New Comment (Rich Markup)
   

You are not logged in

Please log in, so followups can be emailed to you.

 

Sun 22 Feb 2015 06:29:37 AM UTC, comment #1: 

The new symbolic package does not have a symfsolve function, instead providing what looks like a Matlab compatible solve function operating on symbolic types. Closing this bug as won't fix since the symfsolve function is gone along with the old symbolic package.

Mike Miller <mtmiller>
Project Administrator
Sun 28 Sep 2014 12:07:32 AM UTC, original submission:  

For some reason that I do not really understand, the last test in file symfsolve.m is giving now (with Octave 3.8.2) a different result from what it used to give before, even though the solution that is found is fully valid.  This is perhaps due to recent changes in the fsolve function, which is in Octave core.  Here is what I obtain now:

octave:1> symbols
octave:2> x = sym ("x");
octave:3> y = sym ("y");
octave:4> f = x ^ 2 + 3 * x - 1;
octave:5> g = x * y - y ^ 2 + 3;
octave:6> assert (symfsolve ({f, g}, {y==1,x==2}), [1.89004; 0.30278]', 1e-5);
error: ASSERT errors for:  assert (symfsolve ({f, g}, {y == 1, x == 2}),[1.89004; 0.30278]',1e-5)

  Location  |  Observed  |  Expected  |  Reason
    (1)        -1.5873        1.89       Abs err 3.4773 exceeds tol 1e-05

The obvious fix is to change the test in inst/symfsolve.m to read:

%!assert (symfsolve ({f, g}, {y==1,x==2}), [-1.58727; 0.30278]', 1e-5);

Rafael Laboissiere <rlaboiss>

 

(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 mtmiller (Posted a comment)
  • -email is unavailable- added by rlaboiss (Submitted the item)
  •  

    Do you think this task is very important?
    If so, you can add your encouragement to it.
    This task has 0 encouragements so far.

    Only project members can vote.

     

     

     

    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2015-02-22 mtmiller StatusNone => Wont Fix
        Open/ClosedOpen => Closed

    Back to the top


    Powered by Savane 3.5