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/dsep.f | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 math/slalib/dsep.f (limited to 'math/slalib/dsep.f') diff --git a/math/slalib/dsep.f b/math/slalib/dsep.f new file mode 100644 index 00000000..6e7e9fff --- /dev/null +++ b/math/slalib/dsep.f @@ -0,0 +1,61 @@ + DOUBLE PRECISION FUNCTION slDSEP (A1, B1, A2, B2) +*+ +* - - - - - +* D S E P +* - - - - - +* +* Angle between two points on a sphere. +* +* (double precision) +* +* Given: +* A1,B1 d spherical coordinates of one point +* A2,B2 d spherical coordinates of the other point +* +* (The spherical coordinates are [RA,Dec], [Long,Lat] etc, in radians.) +* +* The result is the angle, in radians, between the two points. It +* is always positive. +* +* Called: slDS2C, slDSEPV +* +* Last revision: 7 May 2000 +* +* 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 A1,B1,A2,B2 + + DOUBLE PRECISION V1(3),V2(3) + DOUBLE PRECISION slDSEPV + + + +* Convert coordinates from spherical to Cartesian. + CALL slDS2C(A1,B1,V1) + CALL slDS2C(A2,B2,V2) + +* Angle between the vectors. + slDSEP = slDSEPV(V1,V2) + + END -- cgit