SOLVER fails to find optimal solution

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I appreciate your effort to add a solver to ONLYOFFICE, but the current version fails to find the optimal solution in the below linear programming problem

max z = 3*x1 + 2*x2

subject to

x1 + 3*x2 <= 5
4*x1 + 2*x2 <= 11
x1, x2 nonnegative

The correct optimal solution is

x1 = 2.3
x2 = 0.9
max z = 8.7

but unfortunately the ONLYOFFICE solver finds erroneously the following solution

x1=5
x2=0

which violates the second constraint.

For your convenience, you may download the Excel file from here (my Google Drive).

Please pass this to your development team.

John A. Paravantis

Professor, University of Piraeus

https://www.unipi.gr/en/people/paravantis-john/`Preformatted text`

2

Hey @paravantis, :wave:

Thanks a lot for the detailed report, the problem description, and the example file — this is exactly the kind of feedback that helps us improve!

I’ve already passed everything to the development team for investigation.

I’ll keep you updated right here as soon as there’s progress or a fix.

One small thing: the Google Drive link says “Access denied”.
I’ve sent a request for access — if you could approve it or upload the file directly here (or to ONLYOFFICE DocSpace/kDrive), that would be perfect. Thanks again! :blush:

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4

I am copying the link to the Excel file again below:

This time, I have made sure it’s available for everyone with the link (don’t worry if it says Private).

Best,
John A. Paravantis
University of Piraeus
https://www.unipi.gr/en/people/paravantis-john/

1 Like
5

A post was split to a new topic: Solver tool. GRG Nonlinear method

6

Hey @paravantis, :wave:

Thank you so much for the file and for making it accessible — it’s now downloaded and will be very useful for testing!

We’ve created a bug report for this behavior!

Thanks again for your clear example and for contributing to the community — reports like yours really help us improve!
I’ll keep you posted on any progress. :hugs:

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Hi @paravantis ,
you can try this one: :flexed_biceps:
just fit the min with =1/max

9

Thank you @KarlBreuer
Your plugin sounds interesting. I’ve seen the other thread where you shared it, and we’re looking into it. A colleague of mine will reply there (Here is the nonlinear programming solver. NLP-Solver) once plugin review is finished.
Meanwhile, this thread was related to specific separate bug, and we’re going to fix it in v.9.4.

10

Hello @paravantis

We have just released new version of Desktop Editors that beings fix to the issue discussed in this topic. Please update your app, check out the situation again and share a feedback.

11

Community version 9.3.1.8 (x64 flatpak) still cannot find the optimal solution of the problem mentioned in my previous post.

I don’t see an update to a later version in my Linux Mint Cinnamon.

12

My Linux Mint Cinnamon just updated OnlyOffice to version 9.4.0.

I confirm that the new version finds the correct optimal solution of the problem!

Good job!

1 Like