copy

slalib/mxm.f

@@ -0,0 +1,71 @@
+      SUBROUTINE sla_MXM (A, B, C)
+*+
+*     - - - -
+*      M X M
+*     - - - -
+*
+*  Product of two 3x3 matrices:
+*      matrix C  =  matrix A  x  matrix B
+*
+*  (single precision)
+*
+*  Given:
+*      A      real(3,3)        matrix
+*      B      real(3,3)        matrix
+*
+*  Returned:
+*      C      real(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., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      REAL A(3,3),B(3,3),C(3,3)
+
+      INTEGER I,J,K
+      REAL W,WM(3,3)
+
+
+*  Multiply into scratch matrix
+      DO I=1,3
+         DO J=1,3
+            W=0.0
+            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