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On 9/22/2014 10:10 AM, Chen Zhao wrote: > Hi all, > > I have a follow-up question here. I calculated the eigenvalues and > the eigenvectors and some of them have imaginary terms. The real > terms of the eigenvalues match a 2-fold rotation, but I am just > wondering what the imaginary terms represent. It's been quite a > while since I studied linear algebra. > The eigenvalues for a rotation matrix will have one that is real and the other two complex. The eigenvector that corresponds to the real value is the rotation axis. The other two are not useful for your purpose. By the way, that real eigenvalue has better be equal to one! Dale Tronrud > Thank you so much, Chen > > On Mon, Sep 22, 2014 at 10:41 AM, Philip Kiser <[email protected] > <mailto:[email protected]>> wrote: > > Cool. Glad to help. > > On Mon, Sep 22, 2014 at 10:34 AM, Chen Zhao <[email protected] > <mailto:[email protected]>> wrote: > > Dear Philip, > > Please forgive me! Yes it is eigenvectors that I am looking for. I > was deriving myself and came to the conclusion that R=A^(-1)R'A, > but I just forgot it is eigenvectors, and I forgot what the > eigenvector is originally for. Thank you so much! > > Sincerely, Chen > > On Mon, Sep 22, 2014 at 10:22 AM, Philip Kiser <[email protected] > <mailto:[email protected]>> wrote: > > Hi Chen, > > Wouldn't the fold of the NCS be clear from the PDB file? You could > use superpose to superimpose one monomer onto the next member of > the NCS group, and then take the rotation matrix output from that > program to calculate the eigenvectors for the transformation. The > NCS axis is parallel to one of those eigenvectors. > > Philip > > Philip > > On Mon, Sep 22, 2014 at 10:13 AM, Chen Zhao <[email protected] > <mailto:[email protected]>> wrote: > > Dear all, > > Is there a software that can print out the position and the fold of > a NCS rotational axis from a PDB file? (just something like molrep > self-rotation on a reflection file) I cannot use molrep because the > RMSD between the two copies are too high, and I just want to cut a > certain region for calculation. I don't know whether calculated Fc > from the truncated PDB works in molrep self-RF, but I am thinking > whether there is a more straightforward way. > > Thanks a lot in advance! > > Sincerely, Chen > > > > > -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (MingW32) iEYEARECAAYFAlQgW7QACgkQU5C0gGfAG13IzQCeNPJi+TDEe7v/vI5Pzwm+/Vfb dDEAniquuYawYm3ogMUa8yylMz51xUDQ =bFra -----END PGP SIGNATURE-----
