[Haskell-cafe] Re: Numeric.LinearProgramming - confusion in constructors for bounds

Alberto Ruiz aruiz at um.es
Wed Mar 31 09:57:07 EDT 2010

Hi Ozgur,

You are right, the operators are misleading. I will change them to 
":<=:" and ":>=:". And perhaps the symbol ":&:" for the interval bound 
should also be improved...

Thanks for your suggestion!

Ozgur Akgun wrote:
> Hi everyone and Alberto,
> Numeric.LinearProgramming[1] provides a very nice interface for solving 
> LP optimisation problems, and the well-known simplex algorithm itself. I 
> must say I quite liked the interface it provides, simple yet sufficient.
> But, to my understanding, there is a confusion in the constructor name 
> (symbols actually) for constraints. In LP, one needs to write 
> constraints in the form of ==, <=, or >= only. You /cannot /write a 
> constraint using strict inequalities. The algorithm has nothing wrong, 
> but I guess it would be better to have constructor symbols right. See [2]
> If this is a design choice, I think it should explicitly be stated.
> Regards,
> [1] http://hackage.haskell.org/package/hmatrix-glpk
> [2] 
> http://hackage.haskell.org/packages/archive/hmatrix-glpk/0.1.0/doc/html/Numeric-LinearProgramming.html#t%3ABound 
> -- 
> Ozgur Akgun

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