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Rank-N Update Implementation for the IBM 3090 Vector Facility

IP.com Disclosure Number: IPCOM000100852D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Chang, S: AUTHOR [+2]

Abstract

The rank-n update implementation efficiently uses the IBM System/370 vector instructions and the IBM 3090 cache to perform a rank-n update of an upper triangular matrix.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 61% of the total text.

Rank-N Update Implementation for the IBM 3090 Vector Facility

       The rank-n update implementation efficiently uses the IBM
System/370 vector instructions and the IBM 3090 cache to perform a
rank-n update of an upper triangular matrix.

      The invention is a specific implementation of the rank-n update
that is described in "Tuning the ANSYS Kernel LSOLVE for a Parallel
Computer".  The rank-n update consists of a single VS
FORTRAN-callable subroutine, RANKN, that is implemented in Assembler
H.  The arguments to RANKN consist of the array containing the upper
triangular matrix, the total number of rows in the matrix, the matrix
containing coefficients for each row to be eliminated, the number of
rows to be eliminated, the range of columns to be eliminated, and the
range of rows to be eliminated.

      The major components of the implementation for the IBM 3090VF
are as follows.
-    A loop over vector sections in the range of columns to be
eliminated.  Thus, each vector consists of a range of columns within
a single row of the upper triangular matrix.
-    A loop over rows of the upper triangular matrix in the range
specified that are to be eliminated.
-    An adjustment of the vector length to correctly account for the
triangular structure of the matrix.
-    An inner loop that updates a single row with the number of rows
to be eliminated. The major features of the implementation that we
believe to be new are as follows.
-    Obtaining t...