Michael, Andrew I changed the code and all the variables now have fixed upper bound ( 1000 units). But I am still getting the Numerical instability warnings. In my program, the size of the model increases in each solve. Is the instability because of the increasing problem size or accumulated round-off errors. If latter is the case, is there any way to determine the instability and reset the model when instability is present.
Akhil On Fri, Jul 8, 2011 at 12:54 PM, Michael Hennebry < [email protected]> wrote: > On Fri, 8 Jul 2011, Akhil langer wrote: > > Andrew, >> >> Thanks, Andrew. The NaN problem has been resolved. However, I keep getting >> the following warning: >> >> Warning: numerical instability (primal simplex, phase I) >> >> Please note that I have been using INT_MAX as the upper bound for some >> columns. Could that be the cause of the instability? I can change these >> columns also to be free but that would require some changes in the code. >> Just wanted to check with you if changing the code will remove the >> instability? >> > > That is still rather large. > I'd bite the bullet and make the code changes. > In the alternative, find sensible bounds. > > -- > Michael [email protected] > "Pessimist: The glass is half empty. > Optimist: The glass is half full. > Engineer: The glass is twice as big as it needs to be." >
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