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From: | Samik Raychaudhuri |
Subject: | Re: [Help-glpk] MPS Free format |
Date: | Mon, 12 Jul 2004 10:24:44 -0400 |
User-agent: | Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040514 |
Hello, Yeah I did mean the free MPS format introduced in IBM OSL.I found out that the Coin optimization suit's Clp also does this format change. I had to execute the following command:
clp -keepname off -import a.mps -presolve off -export b.mpsThough it might not be used by many, I think it is useful. The problem I am dealing with has these long variable names which means something in the real world. It would have been great had Glpk solved the same input file. With so many standards around, it's always painful to maintain compatibility .. no doubt.
Regards, -Samik On 7/12/2004 10:00 AM, Andrew Makhorin wrote:
I was referring to the two types of MPS models: fixed format and freeformat. In free format there are no restrictions on the names of the variables etc. GLPSOL supports the fixed format as of now, but I have problems in free format.Do you mean "free MPS format" introduced in IBM OSL? Or something else? There are many packages that allow deviations from the standard MPS/360 format (names longer than 8 chars, arbitrary filed positions, etc.). Glpk supports only the standard MPS/360 format with no deviations. In my opinion, there is no reason to provide glpk with "free MPS format", because it is not widely used and because the MPS format itself is highly inconvenient in all aspects. (I think it would be much better to develop a GNU low-level format for coding lp/mip models. Not XML-based one, of course. :+) Andrew Makhorin
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