bugGNU Octave - Bugs: bug #50495, Plot not correct for...

 
 

bug #50495: Plot not correct for "large" numbers

Submitted by:  None
Submitted on:  Wed 08 Mar 2017 06:31:03 PM UTC  
 
Category: Plotting with OpenGLSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Inaccurate Result
Status: DuplicateAssigned to: None
Originator Name: Tyler RyanOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 4.2.1
Operating System: GNU/Linux

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Thu 09 Mar 2017 05:18:02 AM UTC, comment #3:

This is a duplicate. Closing report.

Use the eps function to check what machine precision is. In this case,

And the example code is using a step size in x of 1 which is below this value, and hence unrecognized.

Rik <rik5>
Project Administrator
Wed 08 Mar 2017 07:43:37 PM UTC, comment #2:

Sorry, I should have mentioned this is the opengl toolkit.

I originally asked on the irc channel and jwe mentioned the single precision bugs reports already filed but the values I'm using (2e7) should be well within the range of a single.

Anonymous
Wed 08 Mar 2017 07:37:38 PM UTC, comment #1:

What graphics toolkit do you use?

Type
graphics_toolkit
at the Octave prompt and report back.

I suspect this is due to the OpenGL toolkits (qt and fltk) using single rather than double precision.
If so this bug report is a duplicate of several others, e.g.,
bug #32980.

Philip Nienhuis <philipnienhuis>
Project Member
Wed 08 Mar 2017 06:31:03 PM UTC, original submission:

Running the below scrip produces and graph where the lines and markers don't match.

I do get the expected output (lines go through markers) if I change the x values to be 0:10;

Anonymous

 

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Attached Files
file #39944:  Figure 1_001.png added by None (15KiB - image/png - Example of figure output)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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  • -unavailable- added by rik5 (Posted a comment)
  • -unavailable- added by None (Submitted the item)
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    Follow 4 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 09 Mar 2017 05:18:02 AM UTCrik5StatusNeed Info=>Duplicate
      Open/ClosedOpen=>Closed
    Wed 08 Mar 2017 07:37:38 PM UTCphilipnienhuisStatusNone=>Need Info
    Wed 08 Mar 2017 06:31:03 PM UTCNoneAttached File-=>Added Figure 1_001.png, #39944

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