Page 1 of 1

Author of ZTGEVC sought

PostPosted: Thu Sep 20, 2018 10:15 am
by Carl Christian
ZTGEVC can be used to compute the user's selection of generalized right/left eigenvectors for the triangular matrix pencil (A,B).
I am studying the source code and have questions that I would dearly like to ask the author related to the construction and solution of certain triangular linear systems Cx = (aA-bB)x = 0.
Obviously, if there exist text discussing the construction of a and b, I would like to obtain a copy.

My immediate goal is to understand why the code is correct and obtain a complete list of the underlying assumptions, such as explicit bounds on the input.

If possible, please alert the author to this message.

Re: Author of ZTGEVC sought

PostPosted: Sun Oct 07, 2018 10:17 pm
by CyLith
I second this request. I have spent a good portion of my life translating Lapack from Fortran to C++, including aggressive early deflation QR iterations, and somehow the triangular eigenvector extraction code still seems vastly more complicated to me. If anyone is an expert on this algorithm, please explain it to us!