## diagonal plus symmetric rank one eigenproblem

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### diagonal plus symmetric rank one eigenproblem

I'd appreciate any advice on how to find all eigenvalues/vectors of a matrix of the form D + a d d^T, where D is positive and diagonal, a is a positive scalar, and d is a vector with positive entries. (Actually, the diagonal elements of D are the squares of the entries of d.) It looks like I should be able to use dlaed3, but I'm having trouble understanding the documentation. Thanks!
gmandrew

Posts: 1
Joined: Thu Jul 07, 2011 1:40 am

### Re: diagonal plus symmetric rank one eigenproblem

hey please refer this paper " mathematical formulation of cuppen's divide and conquer algorithm" u will find the code structure for solving the secular equation and there is a lapack routine slaed4.f ,this uses the middle way method and fixed weight method for solving the equation

solving secular equation stably and efficiently ren-cang li even this paper will help u
bibekkabi

Posts: 1
Joined: Wed Sep 21, 2011 1:44 pm