论文信息 - Improving the Unsymmetric Parallel QR Algorithm on Vector Machines

Improving the Unsymmetric Parallel QR Algorithm on Vector Machines

We present some theoretical and computational improvements to the single/double shift QR algorithm on vector machines. The improvement involves a lookahead algorithm that obtains vector performance better than the high multiplicity shift QR. The strategies presented are numerically similar to those found in such libraries as LAPACK and EISPACK. We provide tests to show improved timings against LAPACK, ESSL, and the vector version of EISPACK on an IBM 3090/VF. We also provide theorems to show theoretical complexity improvements.

Greg Henry

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