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psblas3/base/serial/f77/dlpupd.f

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FortranFixed

C
C Parallel Sparse BLAS version 2.2
C (C) Copyright 2006/2007/2008
C Salvatore Filippone University of Rome Tor Vergata
C Alfredo Buttari University of Rome Tor Vergata
C
C Redistribution and use in source and binary forms, with or without
C modification, are permitted provided that the following conditions
C are met:
C 1. Redistributions of source code must retain the above copyright
C notice, this list of conditions and the following disclaimer.
C 2. Redistributions in binary form must reproduce the above copyright
C notice, this list of conditions, and the following disclaimer in the
C documentation and/or other materials provided with the distribution.
C 3. The name of the PSBLAS group or the names of its contributors may
C not be used to endorse or promote products derived from this
C software without specific written permission.
C
C THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
C ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
C TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
C PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
C BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
C CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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C CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
C ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
C POSSIBILITY OF SUCH DAMAGE.
C
C
20 years ago
C Subroutine DLPUPD(M,N,PERM,B,LDB,BETA,C,LDC,IERROR)
C Purpose
C =======
C
C Computing C <-- PERM B + BETA C
C where PERM is a permutation matrix.
C
C Parameters
C ==========
C
C M - INTEGER
C On entry M specifies the number of rows of matrices
C B and C.
C Unchanged on exit.
C
C N - INTEGER
C On entry N specifies the number of columns of matrices
C B and C.
C Unchanged on exit.
C
C PERM - INTEGER array of dimension (N)
C On entry PERM specifies the values of a permutation matrix.
C Unchanged on exit.
C
C B - DOUBLE PRECISION matrix of dimension (LDB,*)
C On entry: dense matrix.
C Unchanged on exit.
C
C LDB - INTEGER
C On entry LDB holds the value of the leading dimension of B
C Unchanged on exit.
C
C BETA - DOUBLE PRECISION
C On entry: multiplicative constant.
C Unchanged on exit.
C
C C - DOUBLE PRECISION matrix of dimension (LDC,*)
C On entry: dense matrix.
C On exit is updated as shown above.
C
C LDC - INTEGER
C On entry LDC holds the value of the leading dimension of C
C Unchanged on exit.
C
C Note
C ====
C All checks on argument are performed in the calling routines.
C
C
SUBROUTINE DLPUPD(M,N,PERM,B,LDB,BETA,C,LDC)
C .. Scalar Arguments ..
INTEGER M, N, LDB, LDC
DOUBLE PRECISION BETA
C .. Array Arguments ..
INTEGER PERM(*)
DOUBLE PRECISION B(LDB,*), C(LDC,*)
C .. Local Scalars ..
INTEGER I,J
C
C .. Executable Statements ..
C
C Switching on BETA
C
IF (BETA.NE.0.D0) THEN
C
C Performing left permutation and update
C
DO 40 J = 1, N
DO 30 I = 1, M
C(I,J) = B(PERM(I),J) + BETA*C(I,J)
30 CONTINUE
40 CONTINUE
ELSE IF(BETA.EQ.0.D0) THEN
C
C Performing right or left permutation
C
DO 160 J = 1, N
DO 150 I = 1, M
C(I,J) = B(PERM(I),J)
150 CONTINUE
160 CONTINUE
ENDIF
RETURN
END