From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- math/slalib/dmxm.f | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 math/slalib/dmxm.f (limited to 'math/slalib/dmxm.f') diff --git a/math/slalib/dmxm.f b/math/slalib/dmxm.f new file mode 100644 index 00000000..0d319eef --- /dev/null +++ b/math/slalib/dmxm.f @@ -0,0 +1,73 @@ + SUBROUTINE slDMXM (A, B, C) +*+ +* - - - - - +* D M X M +* - - - - - +* +* Product of two 3x3 matrices: +* +* matrix C = matrix A x matrix B +* +* (double precision) +* +* Given: +* A dp(3,3) matrix +* B dp(3,3) matrix +* +* Returned: +* C dp(3,3) matrix result +* +* To comply with the ANSI Fortran 77 standard, A, B and C must +* be different arrays. However, the routine is coded so as to +* work properly on many platforms even if this rule is violated. +* +* Last revision: 26 December 2004 +* +* Copyright P.T.Wallace. All rights reserved. +* +* License: +* This program is free software; you can redistribute it and/or modify +* it under the terms of the GNU General Public License as published by +* the Free Software Foundation; either version 2 of the License, or +* (at your option) any later version. +* +* This program is distributed in the hope that it will be useful, +* but WITHOUT ANY WARRANTY; without even the implied warranty of +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +* GNU General Public License for more details. +* +* You should have received a copy of the GNU General Public License +* along with this program (see SLA_CONDITIONS); if not, write to the +* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +* Boston, MA 02110-1301 USA +* +* Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. +*- + + IMPLICIT NONE + + DOUBLE PRECISION A(3,3),B(3,3),C(3,3) + + INTEGER I,J,K + DOUBLE PRECISION W,WM(3,3) + + +* Multiply into scratch matrix + DO I=1,3 + DO J=1,3 + W=0D0 + DO K=1,3 + W=W+A(I,K)*B(K,J) + END DO + WM(I,J)=W + END DO + END DO + +* Return the result + DO J=1,3 + DO I=1,3 + C(I,J)=WM(I,J) + END DO + END DO + + END -- cgit