The two lists are the same within a factor of -2 and the fact that the R eigenvalues seem to be missing the value 0.
--Chris On Tue, Jan 24, 2012 at 5:13 PM, ANJAN PURKAYASTHA <[email protected]> wrote: > Hi all, > Sorry for this data intensive post. I am a PDL newbie and am writing > multidimensional scaling module in PDL. > I used the following code: my ($eigen_vec, $eigen_val)= > PDL::Math::eigens($g); to generate the eigenvalues (and vectors) for a > matrix $g which is: > [ > [-0.46762857 -0.24672857 0.13132857 0.13132857 0.13132857 0.13132857 > 0.13132857 0.13132857 -0.35872857 0.13132857 -0.24672857 0.16482143 > 0.16482143 0.070871429] > [-0.24672857 -0.46762857 0.13132857 0.13132857 0.13132857 0.13132857 > 0.13132857 0.13132857 -0.24672857 0.13132857 -0.35872857 0.16482143 > 0.16482143 0.070871429] > [ 0.13132857 0.13132857 -0.27791429 -0.15541429 -0.15541429 -0.15541429 > -0.15541429 -0.15541429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [ 0.13132857 0.13132857 -0.15541429 -0.27791429 -0.15541429 -0.15541429 > -0.15541429 -0.15541429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [ 0.13132857 0.13132857 -0.15541429 -0.15541429 -0.27791429 -0.15541429 > -0.15541429 -0.15541429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [ 0.13132857 0.13132857 -0.15541429 -0.15541429 -0.15541429 -0.27791429 > -0.15541429 -0.15541429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [ 0.13132857 0.13132857 -0.15541429 -0.15541429 -0.15541429 -0.15541429 > -0.27791429 -0.15541429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [ 0.13132857 0.13132857 -0.15541429 -0.15541429 -0.15541429 -0.15541429 > -0.15541429 -0.27791429 0.13132857 -0.15541429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [-0.35872857 -0.24672857 0.13132857 0.13132857 0.13132857 0.13132857 > 0.13132857 0.13132857 -0.46762857 0.13132857 -0.24672857 0.16482143 > 0.16482143 0.070871429] > [ 0.13132857 0.13132857 -0.15541429 -0.15541429 -0.15541429 -0.15541429 > -0.15541429 -0.15541429 0.13132857 -0.27791429 0.13132857 0.25967857 > 0.25967857 0.16572857] > [-0.24672857 -0.35872857 0.13132857 0.13132857 0.13132857 0.13132857 > 0.13132857 0.13132857 -0.24672857 0.13132857 -0.46762857 0.16482143 > 0.16482143 0.070871429] > [ 0.16482143 0.16482143 0.25967857 0.25967857 0.25967857 0.25967857 > 0.25967857 0.25967857 0.16482143 0.25967857 0.16482143 -1.2027286 > -1.1127286 -0.16157857] > [ 0.16482143 0.16482143 0.25967857 0.25967857 0.25967857 0.25967857 > 0.25967857 0.25967857 0.16482143 0.25967857 0.16482143 -1.1127286 > -1.2027286 -0.16157857] > [0.070871429 0.070871429 0.16572857 0.16572857 0.16572857 0.16572857 > 0.16572857 0.16572857 0.070871429 0.16572857 0.070871429 -0.16157857 > -0.16157857 -1.1204286] > ] > > The list of eigenvalues I get is: > -0.1089 -0.3329 8.5614601633457e-15 -0.1225 -0.1225 -0.1225 -0.1225 -0.1225 > -2.9792477876937 -0.1225 -0.1089 -1.88386103059169 -0.0900000000000002 > -1.10299118171461 > > However the eigenvalues returned for the same matrix,in R are: > 1.4896239 0.9419305 0.5514956 0.1664500 0.0612500 0.0612500 0.0612500 > 0.0612500 0.0612500 0.0612500 0.0544500 0.0544500 0.0450000 > > The two lists clearly do not match. Any idea where I am going wrong? > > Thank you, > Anjan > > _______________________________________________ > Perldl mailing list > [email protected] > http://mailman.jach.hawaii.edu/mailman/listinfo/perldl > _______________________________________________ Perldl mailing list [email protected] http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
