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Re: [Help-glpk] [Fwd: New input method.]

From: Nigel Galloway
Subject: Re: [Help-glpk] [Fwd: New input method.]
Date: Sat, 23 Apr 2011 06:26:29 -0700

If you have COIN installed it has a class called Sparse Matrix which provides the ability to enter, and many functions to manipulate  a matrix. It has a function to extract that matrix as pointers to arrays of ia ja ar triplets suitable for use in glp_load_matrix. If you don't want to install COIN, the Sparse Matrix class is seperate code which compiles and functions independantlly of COIN.
Nigel Galloway
On Fri, 22 Apr 2011 19:49 +0200, "Pierre Parent" <address@hidden> wrote:

Thank you for answering.


I do agree that we could think of a lot of ways to represent data and that all of them would not be useful. Though I think the first thing you expect for initilizing a table (such as simplex table), is actually a usual matrix, ie a 2 dimentional table, ie a double pointer ('double **matrix' in my exemple), containing only values, no indices. I think it is not actually a representation of the data among others, it is the most intuitive one.


On the other hand, having three 1-dimentional table (2 for indices one for values), as curently done, may be very useful if the matrix has only few values differant from zero; but quite tedious to use in general case. Anyway, in my case adding the other method saved me time.

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