Give meaningful error messages when parsing LPs

[GeorchW]

Currently, parsing errors for LP files result in CoinError exceptions being thrown, without any further information; it does not even give a stack frame or even just a report of the currently executing method. This makes finding out why a specific LP file cannot be parsed take hours instead of seconds (at least if no debugger is attached).

I would suggest to:

• add more meaningful error messages than CoinError
• add line and column numbers to indicate where the problem occurred.

(Opening this issue as requested in coin-or/Clp#146.)

[tkralphs]

Actually, should have said also that this is an issue for CoinUtils, not really Clp. I'm going to transfer it there. We have a lot going on and a small number of developers, though, so can't promise anything.

[jjhforrest]

Not really at home in CoinLpIO - not as easy to clean up messages as I would like. A quick hack gives - on a messed up problem. command line - bin/cbc /tmp/exmip1.lp (default strategy 1) #CoinLpIO ### ERROR: CoinLpIO: is_sense(): string: <<= Line 8 ROW02: xy2 COL02 + 1.1 COL03 <<= 2.1 #CoinLpIO ### ERROR: CoinLpIO: is_sense(): string: <>= Line 13 COL01 <>= 2.5 ### CoinLpIO::readLp(): Variable <>= does not appear in objective function or constraints ### ERROR: Bounds; expect a sense, get: 0 Line 14 0 <= COL02 <= 4.1 ERROR: CoinLpIO::readLp, ### ERROR: Bounds; expect a sense, get: 0 Even if a mess - would that be helpful? John Forrest

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On 25/05/2020 17:04, GeorchW wrote: Currently, parsing errors for LP files result in CoinError exceptions being thrown, without any further information; it does not even give a stack frame or even just a report of the currently executing method. This makes finding out why a specific LP file cannot be parsed take hours instead of seconds (at least if no debugger is attached). I would suggest to: * add more meaningful error messages than |CoinError| * add line and column numbers to indicate where the problem occurred. (Opening this issue as requested in coin-or/Clp#146 <coin-or/Clp#146>.) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#133>, or unsubscribe

[GeorchW]

It's definitely better than nothing. I might be able to tell what the problem with my LP file is with this addition.

[dlaehnemann]

I can only second this. Any extra context information when debugging input would be great. Might have also helped isolating this bug that I found and reported over in issue #144 .