PCA problem

Olga Waupotitsch olga at zorro.cecer.army.mil
Tue Nov 30 16:09:15 EST 1993

In info.grass.user you write:

>Hello Grass Users

>Last week I posted a query about being able to access
>the eigenvectors/eigenvalues for my principal
>components. I then followed Agus' suggestion to use
>m.eigensystem on the output of r.covar. However, I
>whenever I try to pipe the r.covar output file into
>the eigensystem module using 
>	m.eigensystem < inputfile
>I get the error message "This command must be run
>interactively". I also get the same error message
>when I try to pipe directly from r.covar to
>m.eigensystem using
>(echo 3: r.covar map.1,map.2,map.3) | m.eigensystem

>Is there some way of being able to input the (often
>long) covariance matrix into m.eigensystem, without
>having to type in all of the values manually?

>Lesley-Ann Dupigny.

Go to src/imagery/i.pca/cmd
in file main.c
delete lines 216 and 226 (i.e. uncomment lines 217-225, which
print out eigen values and eigen vectors)
then run gmake4.1 in this directory

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