[Top][All Lists]

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

[Help-gsl] hi :-) \o/ I've some problem with eigensystem

From: Giuseppe Marco Randazzo
Subject: [Help-gsl] hi :-) \o/ I've some problem with eigensystem
Date: Thu, 22 Apr 2010 08:34:52 +0200

Hi all! :) first of all i must congratulate with all for this project. Now i 
come to the point. I've read the documentation about the eigensystem and i've 
understood (more or less) how it works. :) I took the example code for a 
computation of eigenvalue end eigenvector for a matrix square of order 4, and 
i've modify the data vector to two and i've changed more stuff signed with 4 
to 2 because is a matrix of order two. So the point of question is this: the 
results that i get have the right values but the signs wrong.  Here i write my 
example and the results that i've to get:

double data[] = { 0.616556, 0.615444,
                  0.615444, 0.716556};

The right results of eigen value and eigen vector:

eigenvalue= ( 0.04908339 )
            ( 1.28402771 )

eigenvectors = ( -0.735179  -0.677873 )
               ( 0.677873    -0.735179 )

The value which i took with the sample code instead are this:

eigenvalue = 0.0490843
eigenvector = 
eigenvalue = 1.28403
eigenvector = 

So, the eigenvalue are ok, also the values of eigenvectors, but the signs are 
not correct :|

The sample code which i've used come from here >>

and is the first example of the page (15.8 Examples)

Now, i do not know where i' m wrong with the code, and if i've not understood 
the right mode the gsl library, or simply if this could be a bug? :-)


zeld :-)

reply via email to

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