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Diffstat (limited to 'math/slalib/imxv.f')
| -rw-r--r-- | math/slalib/imxv.f | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/math/slalib/imxv.f b/math/slalib/imxv.f new file mode 100644 index 00000000..804adef7 --- /dev/null +++ b/math/slalib/imxv.f @@ -0,0 +1,69 @@ + SUBROUTINE slIMXV (RM, VA, VB) +*+ +* - - - - - +* I M X V +* - - - - - +* +* Performs the 3-D backward unitary transformation: +* +* vector VB = (inverse of matrix RM) * vector VA +* +* (single precision) +* +* (n.b. the matrix must be unitary, as this routine assumes that +* the inverse and transpose are identical) +* +* Given: +* RM real(3,3) matrix +* VA real(3) vector +* +* Returned: +* VB real(3) result vector +* +* P.T.Wallace Starlink November 1984 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +* +* 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 + + REAL RM(3,3),VA(3),VB(3) + + INTEGER I,J + REAL W,VW(3) + + + +* Inverse of matrix RM * vector VA -> vector VW + DO J=1,3 + W=0.0 + DO I=1,3 + W=W+RM(I,J)*VA(I) + END DO + VW(J)=W + END DO + +* Vector VW -> vector VB + DO J=1,3 + VB(J)=VW(J) + END DO + + END |