--
You received this message because you are subscribed to a topic in the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ampl/7BZaplNudjs/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ampl+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ampl/reply-77152-1950247029-5780564019-1657953125-34887743%40helpscout.net.
Hi, here attached are the data you requested.
Thanks for the help
On Sat, Jul 16, 2022 at 6:31 AM UTC, AMPL Google Group <am...@googlegroups.com> wrote:
There are some tests that need to be run to determine whether your problem is actually infeasible as presolve says, or is actually feasible as the solver says. Once that is known, it will be possible to determine whether some fix is needed in AMPL or the AMPL-solver interface, or whether you need some different presolve settings.
Can you provide a complete example (with model and data) that shows the behavior that you are describing? Then we can run the tests quickly.
--
Robert Fourer
am...@googlegroups.com
--
You received this message because you are subscribed to a topic in the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ampl/7BZaplNudjs/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ampl+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ampl/reply-77152-1950247029-5790967940-1658302262-717699932%40helpscout.net.
Hello,
in the ampl directory I only have the ampl executable. Where can I download the x-ampl executable from?
Thanks
Sam
On Wed, Jul 20, 2022 at 7:30 AM UTC, AMPL Google Group <am...@googlegroups.com> wrote:
We will need your help to get a "snapshot" of the model and data at the point where the presolve issue occurs. This can be done by running your C++ program again after adding a few statements:
1. Check that you have an executable on your computer for "x-ampl", which is a special version of the "ampl" executable that includes the snapshot feature.
2. In place of "ampl::AMPL ampl;" use the following statements to select the x-ampl executable:
ampl::Environment env("", "x-ampl");
ampl::AMPL ampl(env);
3. After "ampl.solve();" add the following statements to save a snapshot file when the infeasible case occurs:
if (ampl.getValue("solve_result").str() == "infeasible") {
ampl.eval("snapshot > snapshot.run;")
*** STOP ***
}
Here *** STOP *** should be replaced by appropriate C++ statements to exit the loops and end the run.
After running this modified version, you will have a file "snapshot.run" that you can send to us and that we can use to reproduce the presolve issue.
--
Robert Fourer
am...@googlegroups.com
--
You received this message because you are subscribed to a topic in the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ampl/7BZaplNudjs/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ampl+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ampl/reply-77152-1950247029-5794763226-1658406449-1309431764%40helpscout.net.
Hello,
I tried running the code with x-ampl as you specified but I get an error:
error running cplex
termination code 9
On Thu, Jul 21, 2022 at 12:27 PM UTC, AMPL Google Group <am...@googlegroups.com> wrote:
The easiest way is to log in to your account at the AMPL Download Portal, then select "My Downloads" from the menu. The links to the x-ampl downloads are near the bottom of the page. Place the downloaded executable (named x-ampl or x-ampl.exe) in the same folder/directory as your current ampl executable.
Alternatively, after logging in to the Portal you can scroll down to "AMPL & Solvers bundle" and download the "command line bundle" for your platform. Then unpack it and move the x-ampl executable over to the same folder/directory as your current ampl executable.
--
Robert Fourer
am...@googlegroups.com
--
You received this message because you are subscribed to a topic in the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ampl/7BZaplNudjs/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ampl+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ampl/reply-77152-1950247029-5799728768-1658511561-898853930%40helpscout.net.
ampl: solve; presolve, constraint con10[1,13,1,14,1,1]: all variables eliminated, but lower bound = 37.6437 > 0 presolve, constraint con10[1,12,1,14,1,1]: all variables eliminated, but lower bound = 47.5927 > 0 presolve, constraint con10[1,12,1,13,1,1]: all variables eliminated, but lower bound = 37.9127 > 0 presolve, constraint con10[1,11,1,14,1,1]: all variables eliminated, but lower bound = 49.4163 > 0 presolve, constraint con10[1,11,1,13,1,1]: all variables eliminated, but lower bound = 39.7363 > 0 72 presolve messages suppressed.
subject to con10[1,13,1,14,1,1]: t[1,14] - t[1,13] >= alpha[1,13,1,14,1,1] - M * (3 - z[1,13,1] - z[1,14,1] - y[1,13,1,14]);
ampl: display t[1,13].lb, t[1,13].ub; t[1,13].lb = 0 t[1,13].ub = 0 ampl: display t[1,14].lb, t[1,14].ub; t[1,14].lb = 0 t[1,14].ub = 0 ampl: display y[1,13,1,14].lb, y[1,13,1,14].ub; y[1,13,1,14].lb = 1 y[1,13,1,14].ub = 1
ampl: display alpha[1,13,1,14,1,1], M, z[1,13,1], z[1,14,1]; alpha[1,13,1,14,1,1] = 37.6437 M = 1e+06 z[1,13,1] = 1 z[1,14,1] = 1
ampl: option presolve 0; ampl: solve; CPLEX 20.1.0.0: return_mipgap 1 ... Infeasibility row 'c2310220': 0 >= 39.9277. ... CPLEX 20.1.0.0: integer infeasible.
Hello!
To answer your questions:
1) if I replace "x-ampl" with "ampl" I do get the same error.
2) The error occurs at first solve
3) I'm using Linux
4) No
However I noticed that this error appears when I try to simulate a bigger case than the previous one in which I had problems.
In this case it seems that the problem is when I try to initialize a very large array...I'm working on it!
I was able to run the previous case and get the snapshot.run file (attached)...
Thanks a lot for your help!
Sam
On Fri, Jul 22, 2022 at 5:39 PM UTC, AMPL Google Group <am...@googlegroups.com> wrote:
The "termination code 9" can happen with any solver. It indicates that the solver failed to start, or crashed while running, but it does not give any more specific information than that.
Normally this error is not affected by the choice of AMPL version. Can you answer a few more questions that will help to clarify the situation?
1. If you replace
ampl::Environment env("", "x-ampl");
by
ampl::Environment env("", "ampl");
and run again, do you get a the same CPLEX error?
2. Does the error occur at the first solve, or are there some successful solves before the error occurs?
3. Which platform (Windows, Linux, MacOS) are you using?
4. Did you install a new copy of CPLEX at the same time that you added x-ampl?
--
Robert Fourer
am...@googlegroups.com
--
You received this message because you are subscribed to a topic in the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ampl/7BZaplNudjs/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ampl+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ampl/reply-77152-1950247029-5811730609-1658958542-206866675%40helpscout.net.