bugGNU Octave - Bugs: bug #54277, trapz ignores dim argument for a...


bug #54277: trapz ignores dim argument for a row vector

Submitted by:  A.R. Burgers <arb>
Submitted on:  Tue 10 Jul 2018 07:33:26 AM UTC  
Category:  Octave Function Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Fixed Assigned to:  None
Originator Name:  Open/Closed:  Closed
Release:  4.4.0 Operating System:  Any

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( Jump to the original submission)

Wed 11 Jul 2018 06:12:09 AM UTC, comment #6: 

Indeed matlab produces an error:

>> version
ans = ' (R2018a)'

>> trapz ([0:0.5:2;0:0.5:2].',[1:5;1:5].',1)
Error using trapz (line 62)
X must be a vector.

A.R. Burgers <arb>
Tue 10 Jul 2018 10:27:40 PM UTC, comment #5: 

I checked in a changeset to stable that fixes this.  See http://hg.savannah.gnu.org/hgweb/octave/rev/b09ff039e6ff.  Marking as fixed and closing report.

I'd still like to know if Matlab throws an error though.

Rik <rik5>
Project Administrator
Tue 10 Jul 2018 09:46:37 PM UTC, comment #4: 

Okay, I see quite a few problems that need to be fixed.  Could someone test this in Matlab?

trapz ([0:0.5:2;0:0.5:2].',[1:5;1:5].',1)

I think it will produce an error.

Rik <rik5>
Project Administrator
Tue 10 Jul 2018 07:34:03 PM UTC, comment #3: 

Matlab 2018b prerelease:

>> trapz (2, magic (3), 1)
ans =
    18    20    22

Philip Nienhuis <philipnienhuis>
Project Member
Tue 10 Jul 2018 03:11:38 PM UTC, comment #2: 

Since you have access to Matlab, could you also check this syntax?

trapz (2, magic (3), 1)

Rik <rik5>
Project Administrator
Tue 10 Jul 2018 02:39:39 PM UTC, comment #1: 


It gets it correct for column vectors

octave:4> trapz (ones (3,1), 2)
ans =


I'll take a quick look.

Rik <rik5>
Project Administrator
Tue 10 Jul 2018 07:33:26 AM UTC, original submission:  

octave's trapz behaves differently from matlab on row vectors, and appears to ignore the dim argument in this case.

with octave:

>> version
ans = 4.4.0x

>> trapz(ones(1,3),1)
ans = 2

On matlab

>> version
ans = ' (R2018a)'

>> trapz(ones(1,3),1)
ans =   0     0     0

A.R. Burgers <arb>


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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-07-10 rik5 StatusConfirmed => Fixed
        Open/ClosedOpen => Closed
    2018-07-10 rik5 StatusNone => Confirmed

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