Dear all,

I would like to warm-start a MIP using a solution that I know from a heuristic. Therefore, I would like to use the CPLEX-method

"readMIPStarts(name)"

"name" correstponds to the file name where the solution is stored. From what I learned, the file is of the type .mst. In order to understand how the .mst file looks like, I would like to generate one file "result.mst" after solving an easy MIP with the CPLEX method.

"writeMIPStarts(name, start, nb)".

However, both methods are not working and the following error messages are thrown:

"MIPCplex.writeMIPStarts("result.mst",0, 1000);" --> CPLEX error 1422: Could not open file 'result.mst' for writing

"MIPCpex.readMIPStarts("result");" --> CPLEX error 1423: Could not open file 'result.mst' for reading

The file "result.mst" is located in the working directory of the model.

I have created the result.mst file as a text file (result.txt) and renamed it to result.mst manually.

Why am I getting the error messages?

Any help is highly appreciated!

Thank you & best regards,

Jonas

My ILOG CPLEX Optimization Studion version is 12.6.1.0 and I work with ilog script.

asked 23 Jul '15, 06:14

JKCV's gravatar image

JKCV
112
accept rate: 0%


It seems that Cplex either cannot find, or does not have permissions to read the file. Is the file in the place from which you execute Cplex? If not, replace name by readMIPStarts("./this/is/a/relative/path/results.mst"); Alternative, if you are using linux, are your read/write/execute permissions correct?

You can also try loading the file through the Interactive optimizer to see whether the result is different. E.g. use the read command in the interactive optimizer: read /full/path/to/your/start/file/result.mst

link

answered 23 Jul '15, 10:45

Joris%20Kinable's gravatar image

Joris Kinable
3381213
accept rate: 16%

Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here

By RSS:

Answers

Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text](http://url.com/ "Title")
  • image?![alt text](/path/img.jpg "Title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Tags:

×191
×6
×2
×1
×1

Asked: 23 Jul '15, 06:14

Seen: 1,658 times

Last updated: 23 Jul '15, 16:50

OR-Exchange! Your site for questions, answers, and announcements about operations research.