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{ Category Archives } Computing

Gurobi software now available for download

I am behind Erwin Kalvelagen, who writes an extremely useful blog where many challenging modeling problems are solved (this is one of my “must read” blogs), in announcing that Gurobi’s standalone software is now available.  I particularly like that the trial version is 500 variables and 500 constraints, which is large enough to see how […]

Microsoft Solver Foundation: YAML?

Is the Microsoft Solver Foundation Yet Another Modeling Language? I have some views at the INFORMS Practice Conference Blog. Best part of the workshop: the tagline “The Right Decision”. Perhaps INFORMS should have used that instead of “The Science of Better”. Microsoft Solver Foundation became public late in 2008, and I have been curious what […]

Test Gurobi yourself!

In keeping with an unusually awesome collection of comments, Daniel Fylstra of Frontline Systems wrote regarding the new linear/integer programming software from Gurobi (apologies for the self-linking, but, hey!, it’s my blog!): Although Gurobi Optimization plans to offer the Gurobi Solver directly (with its own APIs and tool set) starting in April, it’s available in […]

What stops you from using Open Source in Operations Research?

In the discussion of CPLEX versus Gurobi software, the discussion took an interesting turn when it came to open source (like that of COIN-OR).  Sebastian, bemoaning the cost of commercial packages such as CPLEX said: I think another long-term way to make OR feasible in situations where the cost of Cplex cannot be justified is […]

Gurobi versus CPLEX benchmarks

Hans Mittelmann has released some benchmark results comparing CPLEX 11.2 with the first version of Gurobi‘s code (1.02) in both sequential and parallel (4 processor) mode.  Mosek’s sequential code is also included in the test.  Let me highlight some of the lines: ================================================================= s problem CPLEX1 GUROBI1 MOSEK1 CPLEX4 GUROBI4 —————————————————————– air04 9 18 49 […]

Bugs and Modeling

The web was all abuzz on December 31 as the 30Gig version of the Microsoft Zune players all stopped working.  What was up?  Was it a terrorist attack?  Solar flares?  A weird Y2K bug almost a decade later? The truth is a bit prosaic:  there was simply a bug related to leap years.  Since the […]

How far does Santa Travel?

As we all know, Santa Claus has to visit every (good) little girl and boy all in one night.  Fortunately, due to the time zones, he has about 24 hours to do so.  Now the earth is about 25,000 miles around, so he could zip around the earth in that distance (as an aside, I […]

Need for Parallelism

The operations research world is crying out for better parallel approaches to our problems. Note that for $10,000, you can buy a NVIDIA Tesla Personal Supercomputer, with speeds up to 4 teraflops (which, unless I am reading the graph wrong, easily puts it in the top 500 supercomputers at Top 500). The catch? You get […]

Knuth and Multicore Systems

Donald Knuth has been publishing “fascicles” from his Volume 4 (Combinatorial Algorithms) of his epic The Art of Computer Programming. These are shortish (100-150 page) sub-chapters of a work on an area that expands faster than Don can write. You can download some of the preliminary versions on Knuth’s page to get the flavor. Knuth […]

ILOG Optimization Decision Manager Hands On

I sat through (OK, half of) the ILOG workshop on their Optimization Decision Manager.  The ILOG ODM can be seen as a front-end to the rest of the ILOG Optimization systems (like OPL).  I would think of it as a super-sized way of doing version control and what-if analysis.  I use ILOG software in a […]