Abstract
Alternatives are considered for computing the projection of a vector onto the nullspace of a matrix, as is required to compute the step direction for the Karmarkar projective algorithm. Among the possibilities considered are forming and factoring the normal matrix, and working with a larger but sparser extended matrix. The extended matrices are symmetric but indefinite. A modification to the Harwell MA27 set of subroutines to make them more efficient for indefinite matrices is presented. Computational results are given to support the conclusion that computing these projections using one of the extended matrices offers significant computational advantages over the other alternatives with which it is compared.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
