| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palEpco
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| 5 |
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| 6 | * Purpose:
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| 7 | * Convert an epoch into the appropriate form - 'B' or 'J'
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| 8 |
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| 9 | * Language:
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| 10 | * Starlink ANSI C
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| 11 |
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| 12 | * Type of Module:
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| 13 | * Library routine
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| 14 |
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| 15 | * Invocation:
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| 16 | * double palEpco( char k0, char k, double e );
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| 17 |
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| 18 | * Arguments:
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| 19 | * k0 = char (Given)
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| 20 | * Form of result: 'B'=Besselian, 'J'=Julian
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| 21 | * k = char (Given)
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| 22 | * Form of given epoch: 'B' or 'J'.
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| 23 |
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| 24 | * Description:
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| 25 | * Converts a Besselian or Julian epoch to a Julian or Besselian
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| 26 | * epoch.
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| 27 |
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| 28 | * Authors:
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| 29 | * PTW: Patrick T. Wallace
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| 30 | * TIMJ: Tim Jenness (JAC, Hawaii)
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| 31 | * {enter_new_authors_here}
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| 32 |
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| 33 | * Notes:
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| 34 | * - The result is always either equal to or very close to
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| 35 | * the given epoch E. The routine is required only in
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| 36 | * applications where punctilious treatment of heterogeneous
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| 37 | * mixtures of star positions is necessary.
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| 38 | * - k and k0 are case insensitive. This differes slightly from the
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| 39 | * Fortran SLA implementation.
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| 40 | * - k and k0 are not validated. They are interpreted as follows:
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| 41 | * o If k0 and k are the same the result is e
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| 42 | * o If k0 is 'b' or 'B' and k isn't the conversion is J to B.
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| 43 | * o In all other cases, the conversion is B to J.
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| 44 |
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| 45 | * History:
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| 46 | * 2012-03-01 (TIMJ):
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| 47 | * Initial version. Documentation from SLA/F.
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| 48 | * Adapted with permission from the Fortran SLALIB library.
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| 49 | * {enter_further_changes_here}
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| 50 |
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| 51 | * Copyright:
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| 52 | * Copyright (C) 1995 Rutherford Appleton Laboratory
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| 53 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 54 | * All Rights Reserved.
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| 55 |
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| 56 | * Licence:
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| 57 | * This program is free software; you can redistribute it and/or
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| 58 | * modify it under the terms of the GNU General Public License as
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| 59 | * published by the Free Software Foundation; either version 3 of
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| 60 | * the License, or (at your option) any later version.
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| 61 | *
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| 62 | * This program is distributed in the hope that it will be
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| 63 | * useful, but WITHOUT ANY WARRANTY; without even the implied
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| 64 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| 65 | * PURPOSE. See the GNU General Public License for more details.
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| 66 | *
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| 67 | * You should have received a copy of the GNU General Public License
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| 68 | * along with this program; if not, write to the Free Software
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| 69 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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| 70 | * USA.
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| 71 |
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| 72 | * Bugs:
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| 73 | * {note_any_bugs_here}
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| 74 | *-
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| 75 | */
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| 76 |
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| 77 | #include "pal.h"
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| 78 | #include "pal1sofa.h"
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| 79 |
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| 80 | #include <ctype.h>
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| 81 |
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| 82 | double palEpco( char k0, char k, double e ) {
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| 83 |
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| 84 | double new_epoch = 0.0;
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| 85 | double djm;
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| 86 | double djm0;
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| 87 |
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| 88 | /* Use upper case */
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| 89 | k0 = toupper( k0 );
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| 90 | k = toupper( k );
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| 91 |
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| 92 | if (k == k0) {
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| 93 | new_epoch = e;
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| 94 | } else if (k0 == 'B') {
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| 95 | eraEpj2jd( e, &djm0, &djm );
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| 96 | new_epoch = eraEpb( djm0, djm );
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| 97 | } else {
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| 98 | eraEpb2jd( e, &djm0, &djm );
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| 99 | new_epoch = eraEpj( djm0, djm );
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| 100 | }
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| 101 | return new_epoch;
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| 102 | }
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