[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Help-glpk] GLPK for Pattern Recognition

From: Nigel Galloway
Subject: Re: [Help-glpk] GLPK for Pattern Recognition
Date: Tue, 1 Sep 2009 13:14:22 +0100

> ----- Original Message -----
You may find that it helps to seperate finding the best fit from finding the
points which define the line. When I was looking at this earlier in the year I
came up with yacfs.mod (see glpk examples). BigMing that produces good results
for test data which actually represents a single line.

However general data doesn't always provide insight that a special case does.
Looking at seperating two paralell lines proved difficult because if you have a
good line it wants to be mid way between the two.

Not careing about the line being a good fit produces attachments and
. While neither line is a good fit it does in each case identify the
points which lie on a line. parl2.jpg also demonstrates that it chooses the
line with most points. The points on the line can then be taken and yacfs.mod
applied to find the best fit.

Attachments,, and show the
algorithm applied to the original test data with different degrees of tolerance.

I applied the algorithm to your test data with different degrees of tolerance,
see attachments, and

> From: "Gianluca Cerminara" <address@hidden>
> To: address@hidden
> Subject: [Help-glpk] GLPK for Pattern Recognition
> Date: Thu, 27 Aug 2009 00:20:46 +0400
> Hi,
>       I'm a new user of your nice library. We are trying to implement an
> algorithm  for track fitting and pattern recognition for an HEP
> experiment at CERN based on MIP and LP techniques as described in the note:
> The first prototype is working nicely but we are experiencing some
> performance problems: the speed of the algorithm is not yet competitive.
> Since I'm not an expert in linear programming I need some help to
> understand if some of the options of the GLPK APIs can help.
> In particular what are the pros and cons of calling glp_intopt after
> having performed the LP relaxation with the glp_simplex instead of
> calling the built-in presolver?
> Any reference would be appreciated.
> We are using version 4.39.
> Thanks in advance for any feedback,
> Best regards,
>       G
> --
> --------------------------
> Gianluca Cerminara
> _______________________________________________
> Help-glpk mailing list
> address@hidden


Surf the Web in a faster, safer and easier way:
Download Opera 9 at

Powered by Outblaze

reply via email to

[Prev in Thread] Current Thread [Next in Thread]