-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm trying to understand some C code in an R package I'm using. I'm address this question here as it's matrix algebra...and I'm no pro at that!
the C command reads: double alpha = 1.0, beta = 0.0; dsyrk_("L", "N", nGenes, nGenes, & alpha, mat1, nGenes, & beta, mat2, nGenes); - From google, I've found out that dsyrk is for performing one of the symmetric rank k operations - whatever that means!? From here: http://linux.die.net/man/l/dsyrk I've found that the calculation being performed is: alpha*A*A' + beta*C However, since alpha is 1 and beta is 0, this reduces to: => 1*A*A' + 0*C => A*A' Which is simply the cross product....am I correct? Cheers, Nath - -- - -------------------------------------------------------- Dr. Nathan S. Watson-Haigh OCE Post Doctoral Fellow CSIRO Livestock Industries Queensland Bioscience Precinct St Lucia, QLD 4067 Australia Tel: +61 (0)7 3214 2922 Fax: +61 (0)7 3214 2900 Web: http://www.csiro.au/people/Nathan.Watson-Haigh.html - -------------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAklkGVYACgkQ9gTv6QYzVL73HgCgvx4OCxcuczv8nd0n6gOEPFYa w3UAnAnDIkvPDen9p7ahz+BdG47V/D/S =gSGC -----END PGP SIGNATURE----- ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.