is_sense parsing error when `<` at position 1023 in a constraint line
dlaehnemann opened this issue · 3 comments
dlaehnemann commented
I've been tripped up by a very weird bug, that led to a line parsing failure and then down the line to renamed variables, so that I could not use the eventual solution. Here's the minimal example to reproduce the problem (simply rename to the extension '.lp, GitHub doesn't allow uploads with that extension...):
When running cbc buffer_size_issue.lp solve on it, it throws:
Welcome to the CBC MILP Solver
Version: 2.10.5
Build Date: Dec 8 2020
command line - cbc weird_corner_case.lp solve (default strategy 1)
### ERROR: CoinLpIO: is_sense(): string: <
CoinLpIO::readLp(): Maximization problem reformulated as minimization
### CoinLpIO::is_invalid_name(): Name < contains illegal character '<'
### CoinLpIO::are_invalid_names(): Invalid name: vnames[63]: <
### CoinLpIO::readLp(): Invalid column names
Now using default column names.
As deleting any single char in the c6708: line makes this error go away, and the < char (from <=) is in position 1023 of the line, and the buffer size for parsing is 1024, I am assuming it is something to do with this combination chopping up the <= and then is_sense complaining that there's only the < and no = following it in the buffer. I guess this special requires explicit handling in is_sense and maybe elsewhere, as well?
jjhforrest commented
As other solvers seem to allow any length line, I suppose we ought to
fix. Will see how easy it is to fix in a reasonably elegant way.
John Forrest
…On 17/02/2021 16:04, David Laehnemann wrote:
I've been tripped up by a very weird bug, that led to a line parsing
failure and then down the line to renamed variables, so that I could not
use the eventual solution. Here's the minimal example to reproduce the
problem (simply rename to the extension |'.lp|, GitHub doesn't allow
uploads with that extension...):
buffer_size_issue.txt
<https://github.com/coin-or/CoinUtils/files/5996907/buffer_size_issue.txt>
When running |cbc buffer_size_issue.lp solve| on it, it throws:
|Welcome to the CBC MILP Solver Version: 2.10.5 Build Date: Dec 8 2020
command line - cbc weird_corner_case.lp solve (default strategy 1) ###
ERROR: CoinLpIO: is_sense(): string: < CoinLpIO::readLp(): Maximization
problem reformulated as minimization ### CoinLpIO::is_invalid_name():
Name < contains illegal character '<' ### CoinLpIO::are_invalid_names():
Invalid name: vnames[63]: < ### CoinLpIO::readLp(): Invalid column names
Now using default column names. |
As deleting any single char in the |c6708:| line makes this error go
away, and the |<| char (from |<=|) is in position 1023 of the line, and
the buffer size for parsing is 1024, I am assuming it is something to do
with this combination chopping up the |<=| and then |is_sense|
complaining that there's only the |<| and no |=| following it in the
buffer. I guess this special requires explicit handling in is_sense and
maybe elsewhere, as well?
—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
<#144>, or unsubscribe
<https://github.com/notifications/unsubscribe-auth/ABWJYHAXO6GSNZEDXSUSNGDS7PSKNANCNFSM4XYTUD7Q>.
jjhforrest commented
David,
Hopefully fixed in master.
I think the code should now cope with lines of any length and give the
correct line number. I am not very familiar with code, so have not
tried to redo error messages entirely. I agree that some error messags
are not obviously easy to decode - this partly because the format is so
flexible. So to test error handling I added a random ++. This was only
picked up as error at very end when the code said + was an invalid name
- because it had taken the first + as part of equation. It found the
error and fixing everything may not be worthwhile.
John Forrest
…On 17/02/2021 16:04, David Laehnemann wrote:
I've been tripped up by a very weird bug, that led to a line parsing
failure and then down the line to renamed variables, so that I could not
use the eventual solution. Here's the minimal example to reproduce the
problem (simply rename to the extension |'.lp|, GitHub doesn't allow
uploads with that extension...):
buffer_size_issue.txt
<https://github.com/coin-or/CoinUtils/files/5996907/buffer_size_issue.txt>
When running |cbc buffer_size_issue.lp solve| on it, it throws:
|Welcome to the CBC MILP Solver Version: 2.10.5 Build Date: Dec 8 2020
command line - cbc weird_corner_case.lp solve (default strategy 1) ###
ERROR: CoinLpIO: is_sense(): string: < CoinLpIO::readLp(): Maximization
problem reformulated as minimization ### CoinLpIO::is_invalid_name():
Name < contains illegal character '<' ### CoinLpIO::are_invalid_names():
Invalid name: vnames[63]: < ### CoinLpIO::readLp(): Invalid column names
Now using default column names. |
As deleting any single char in the |c6708:| line makes this error go
away, and the |<| char (from |<=|) is in position 1023 of the line, and
the buffer size for parsing is 1024, I am assuming it is something to do
with this combination chopping up the |<=| and then |is_sense|
complaining that there's only the |<| and no |=| following it in the
buffer. I guess this special requires explicit handling in is_sense and
maybe elsewhere, as well?
—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
<#144>, or unsubscribe
<https://github.com/notifications/unsubscribe-auth/ABWJYHAXO6GSNZEDXSUSNGDS7PSKNANCNFSM4XYTUD7Q>.
dlaehnemann commented