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Errors in reading mps file #209

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natebragg opened this issue Sep 22, 2022 · 5 comments
Open

Errors in reading mps file #209

natebragg opened this issue Sep 22, 2022 · 5 comments

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@natebragg
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When trying to upload this mps file to neos, I get the following error:

No MAX/MIN found after OBJSENSE
Coin3005W No match for row OBJROW at line 10 <     C0000000  OBJROW    1.             R0000000  1. >
@tkralphs tkralphs transferred this issue from coin-or/SYMPHONY Apr 12, 2023
@tkralphs
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I transferred this issue to coin-or/CoinUtils because that is where the MPS reader lives. I suspect that this is a case of an MPS problem that is actually in free format, but the reader is treating it as being in the standard fixed format. There have been some improvements in the MPS reader in the master branch that my address this. I'll let @jjhforrest weigh in.

@jjhforrest
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The file is not in the correct format, but the error message is wrong.
The correct format for the Cplex extension to MPS format has MIN or MAX on the next card - not on the same card.

The simplest thing to do is allow that on the same card (at present it is ignored anyway). Done in stable and master.

@jjhforrest
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Modified master so Clp or OsiClp sets optimization direction to maximize if MAX found

@natebragg
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If the file is in the incorrect format, that is an independent issue, as I exclusively generate MPS files using CBC's writeMps API call. My actual problems are constructed using the API, and this file was generated from one of my constructed problems.

@jjhforrest
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I do not understand how that file was generated using Cbc's writeMps. There is no statement that writes an image with OBJSENSE but the file infeasible.mps has OBJSENSE.

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