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question about netlib's lapack vs matlab's lapack; degqrf

PostPosted: Tue Sep 14, 2010 11:54 am
by pepollopep
I have a question about timing differences between degqrf downloaded and installed from netlib vs. running the function qr in matlab, which I had understood to be a call to degqrf. When I find the qr decomposition of tall skinny matrices A_1 and A_2 of sizes 60000x190 and 60000x200 with degqrf from netlib (using the optimal work size), the run time is larger for A_2. but when I run the same computation with matlab's qr, the larger matrix returns much more quickly. Any insight on the difference between matlab's qr and netlib's degqrf would be appreciated.

thanks!