1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
//
// GENERATED FILE
//
use super::*;
use crate::SpiceContext;
use f2rust_std::*;
const CTRSIZ: i32 = 2;
const PMTMP: &[u8] = b"BODY#_PM";
const OVRTMP: &[u8] = b"BODY#_PGR_POSITIVE_LON";
const EARTH: i32 = 399;
const KVNMLN: i32 = 32;
const LNSIZE: i32 = 80;
const MOON: i32 = 301;
const SENSLN: i32 = 4;
const SUN: i32 = 10;
const MAXL: i32 = 36;
struct SaveVars {
SVCTR1: StackArray<i32, 2>,
SVBODY: Vec<u8>,
SVBDID: i32,
SVFND1: bool,
FIRST: bool,
}
impl SaveInit for SaveVars {
fn new() -> Self {
let mut SVCTR1 = StackArray::<i32, 2>::new(1..=CTRSIZ);
let mut SVBODY = vec![b' '; MAXL as usize];
let mut SVBDID: i32 = 0;
let mut SVFND1: bool = false;
let mut FIRST: bool = false;
FIRST = true;
Self {
SVCTR1,
SVBODY,
SVBDID,
SVFND1,
FIRST,
}
}
}
/// Derivative of planetographic w.r.t. rectangular
///
/// Compute the Jacobian matrix of the transformation from
/// rectangular to planetographic coordinates.
///
/// # Brief I/O
///
/// ```text
/// VARIABLE I/O DESCRIPTION
/// -------- --- --------------------------------------------------
/// BODY I Body with which coordinate system is associated.
/// X I X-coordinate of point.
/// Y I Y-coordinate of point.
/// Z I Z-coordinate of point.
/// RE I Equatorial radius of the reference spheroid.
/// F I Flattening coefficient.
/// JACOBI O Matrix of partial derivatives.
/// ```
///
/// # Detailed Input
///
/// ```text
/// BODY is the name of the body with which the planetographic
/// coordinate system is associated.
///
/// BODY is used by this routine to look up from the
/// kernel pool the prime meridian rate coefficient giving
/// the body's spin sense. See the $Files and $Particulars
/// header sections below for details.
///
/// X,
/// Y,
/// Z are the rectangular coordinates of the point at
/// which the Jacobian of the map from rectangular
/// to planetographic coordinates is desired.
///
/// RE is the equatorial radius of the reference spheroid.
///
/// F is the flattening coefficient = (RE-RP) / RE, where RP
/// is the polar radius of the spheroid. (More importantly
/// RP = RE*(1-F).)
/// ```
///
/// # Detailed Output
///
/// ```text
/// JACOBI is the matrix of partial derivatives of the conversion
/// from rectangular to planetographic coordinates. It
/// has the form
///
/// .- -.
/// | DLON/DX DLON/DY DLON/DZ |
/// | DLAT/DX DLAT/DY DLAT/DZ |
/// | DALT/DX DALT/DY DALT/DZ |
/// `- -'
///
/// evaluated at the input values of X, Y, and Z.
/// ```
///
/// # Exceptions
///
/// ```text
/// 1) If the body name BODY cannot be mapped to a NAIF ID code,
/// and if BODY is not a string representation of an integer,
/// the error SPICE(IDCODENOTFOUND) is signaled.
///
/// 2) If the kernel variable
///
/// BODY<ID code>_PGR_POSITIVE_LON
///
/// is present in the kernel pool but has a value other
/// than one of
///
/// 'EAST'
/// 'WEST'
///
/// the error SPICE(INVALIDOPTION) is signaled. Case
/// and blanks are ignored when these values are interpreted.
///
/// 3) If polynomial coefficients for the prime meridian of BODY
/// are not available in the kernel pool, and if the kernel
/// variable BODY<ID code>_PGR_POSITIVE_LON is not present in
/// the kernel pool, the error SPICE(MISSINGDATA) is signaled.
///
/// 4) If the equatorial radius is non-positive, the error
/// SPICE(VALUEOUTOFRANGE) is signaled.
///
/// 5) If the flattening coefficient is greater than or equal to
/// one, the error SPICE(VALUEOUTOFRANGE) is signaled.
///
/// 6) If the input point is on the Z-axis (X = 0 and Y = 0), the
/// Jacobian matrix is undefined, an error is signaled by a
/// routine in the call tree of this routine.
/// ```
///
/// # Files
///
/// ```text
/// This routine expects a kernel variable giving BODY's prime
/// meridian angle as a function of time to be available in the
/// kernel pool. Normally this item is provided by loading a PCK
/// file. The required kernel variable is named
///
/// BODY<body ID>_PM
///
/// where <body ID> represents a string containing the NAIF integer
/// ID code for BODY. For example, if BODY is 'JUPITER', then
/// the name of the kernel variable containing the prime meridian
/// angle coefficients is
///
/// BODY599_PM
///
/// See the PCK Required Reading for details concerning the prime
/// meridian kernel variable.
///
/// The optional kernel variable
///
/// BODY<body ID>_PGR_POSITIVE_LON
///
/// also is normally defined via loading a text kernel. When this
/// variable is present in the kernel pool, the prime meridian
/// coefficients for BODY are not required by this routine. See the
/// $Particulars section for details.
/// ```
///
/// # Particulars
///
/// ```text
/// When performing vector calculations with velocities it is usually
/// most convenient to work in rectangular coordinates. However, once
/// the vector manipulations have been performed, it is often
/// desirable to convert the rectangular representations into
/// planetographic coordinates to gain insights about phenomena in
/// this coordinate frame.
///
/// To transform rectangular velocities to derivatives of coordinates
/// in a planetographic system, one uses the Jacobian of the
/// transformation between the two systems.
///
/// Given a state in rectangular coordinates
///
/// ( x, y, z, dx, dy, dz )
///
/// the velocity in planetographic coordinates is given by the matrix
/// equation:
/// t | t
/// (dlon, dlat, dalt) = JACOBI| * (dx, dy, dz)
/// |(x,y,z)
///
/// This routine computes the matrix
///
/// |
/// JACOBI|
/// |(x, y, z)
///
///
/// The planetographic definition of latitude is identical to the
/// planetodetic (also called "geodetic" in SPICE documentation)
/// definition. In the planetographic coordinate system, latitude is
/// defined using a reference spheroid. The spheroid is
/// characterized by an equatorial radius and a polar radius. For a
/// point P on the spheroid, latitude is defined as the angle between
/// the X-Y plane and the outward surface normal at P. For a point P
/// off the spheroid, latitude is defined as the latitude of the
/// nearest point to P on the spheroid. Note if P is an interior
/// point, for example, if P is at the center of the spheroid, there
/// may not be a unique nearest point to P.
///
/// In the planetographic coordinate system, longitude is defined
/// using the spin sense of the body. Longitude is positive to the
/// west if the spin is prograde and positive to the east if the spin
/// is retrograde. The spin sense is given by the sign of the first
/// degree term of the time-dependent polynomial for the body's prime
/// meridian Euler angle "W": the spin is retrograde if this term is
/// negative and prograde otherwise. For the sun, planets, most
/// natural satellites, and selected asteroids, the polynomial
/// expression for W may be found in a SPICE PCK kernel.
///
/// The earth, moon, and sun are exceptions: planetographic longitude
/// is measured positive east for these bodies.
///
/// If you wish to override the default sense of positive longitude
/// for a particular body, you can do so by defining the kernel
/// variable
///
/// BODY<body ID>_PGR_POSITIVE_LON
///
/// where <body ID> represents the NAIF ID code of the body. This
/// variable may be assigned either of the values
///
/// 'WEST'
/// 'EAST'
///
/// For example, you can have this routine treat the longitude
/// of the earth as increasing to the west using the kernel
/// variable assignment
///
/// BODY399_PGR_POSITIVE_LON = 'WEST'
///
/// Normally such assignments are made by placing them in a text
/// kernel and loading that kernel via FURNSH.
///
/// The definition of this kernel variable controls the behavior of
/// the SPICELIB planetographic routines
///
/// PGRREC
/// RECPGR
/// DPGRDR
/// DRDPGR
///
/// It does not affect the other SPICELIB coordinate conversion
/// routines.
/// ```
///
/// # Examples
///
/// ```text
/// The numerical results shown for this example may differ across
/// platforms. The results depend on the SPICE kernels used as
/// input, the compiler and supporting libraries, and the machine
/// specific arithmetic implementation.
///
///
/// 1) Find the planetographic state of the earth as seen from
/// Mars in the J2000 reference frame at January 1, 2005 TDB.
/// Map this state back to rectangular coordinates as a check.
///
/// Use the meta-kernel shown below to load the required SPICE
/// kernels.
///
///
/// KPL/MK
///
/// File name: dpgrdr_ex1.tm
///
/// This meta-kernel is intended to support operation of SPICE
/// example programs. The kernels shown here should not be
/// assumed to contain adequate or correct versions of data
/// required by SPICE-based user applications.
///
/// In order for an application to use this meta-kernel, the
/// kernels referenced here must be present in the user's
/// current working directory.
///
/// The names and contents of the kernels referenced
/// by this meta-kernel are as follows:
///
/// File name Contents
/// --------- --------
/// de421.bsp Planetary ephemeris
/// pck00008.tpc Planet orientation and
/// radii
/// naif0009.tls Leapseconds
///
///
/// \begindata
///
/// KERNELS_TO_LOAD = ( 'de421.bsp',
/// 'pck00008.tpc',
/// 'naif0009.tls' )
///
/// \begintext
///
/// End of meta-kernel
///
///
/// Example code begins here.
///
///
/// PROGRAM DPGRDR_EX1
/// IMPLICIT NONE
///
/// C
/// C SPICELIB functions
/// C
/// DOUBLE PRECISION RPD
/// C
/// C Local variables
/// C
/// DOUBLE PRECISION ALT
/// DOUBLE PRECISION DRECTN ( 3 )
/// DOUBLE PRECISION ET
/// DOUBLE PRECISION F
/// DOUBLE PRECISION JACOBI ( 3, 3 )
/// DOUBLE PRECISION LAT
/// DOUBLE PRECISION LON
/// DOUBLE PRECISION LT
/// DOUBLE PRECISION PGRVEL ( 3 )
/// DOUBLE PRECISION RADII ( 3 )
/// DOUBLE PRECISION RE
/// DOUBLE PRECISION RECTAN ( 3 )
/// DOUBLE PRECISION RP
/// DOUBLE PRECISION STATE ( 6 )
///
/// INTEGER N
///
/// C
/// C Load SPK, PCK, and LSK kernels, use a meta kernel for
/// C convenience.
/// C
/// CALL FURNSH ( 'dpgrdr_ex1.tm' )
///
/// C
/// C Look up the radii for Mars. Although we
/// C omit it here, we could first call BADKPV
/// C to make sure the variable BODY499_RADII
/// C has three elements and numeric data type.
/// C If the variable is not present in the kernel
/// C pool, BODVRD will signal an error.
/// C
/// CALL BODVRD ( 'MARS', 'RADII', 3, N, RADII )
///
/// C
/// C Compute flattening coefficient.
/// C
/// RE = RADII(1)
/// RP = RADII(3)
/// F = ( RE - RP ) / RE
///
/// C
/// C Look up the geometric state of earth as seen from Mars at
/// C January 1, 2005 TDB, relative to the J2000 reference
/// C frame.
/// C
/// CALL STR2ET ( 'January 1, 2005 TDB', ET )
///
/// CALL SPKEZR ( 'Earth', ET, 'J2000', 'LT+S',
/// . 'Mars', STATE, LT )
///
/// C
/// C Convert position to planetographic coordinates.
/// C
/// CALL RECPGR ( 'MARS', STATE, RE, F, LON, LAT, ALT )
///
/// C
/// C Convert velocity to planetographic coordinates.
/// C
///
/// CALL DPGRDR ( 'MARS', STATE(1), STATE(2), STATE(3),
/// . RE, F, JACOBI )
///
/// CALL MXV ( JACOBI, STATE(4), PGRVEL )
///
/// C
/// C As a check, convert the planetographic state back to
/// C rectangular coordinates.
/// C
/// CALL PGRREC ( 'MARS', LON, LAT, ALT, RE, F, RECTAN )
///
/// CALL DRDPGR ( 'MARS', LON, LAT, ALT, RE, F, JACOBI )
///
/// CALL MXV ( JACOBI, PGRVEL, DRECTN )
///
///
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Rectangular coordinates:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' X (km) = ', STATE(1)
/// WRITE(*,*) ' Y (km) = ', STATE(2)
/// WRITE(*,*) ' Z (km) = ', STATE(3)
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Rectangular velocity:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' dX/dt (km/s) = ', STATE(4)
/// WRITE(*,*) ' dY/dt (km/s) = ', STATE(5)
/// WRITE(*,*) ' dZ/dt (km/s) = ', STATE(6)
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Ellipsoid shape parameters: '
/// WRITE(*,*) ' '
/// WRITE(*,*) ' Equatorial radius (km) = ', RE
/// WRITE(*,*) ' Polar radius (km) = ', RP
/// WRITE(*,*) ' Flattening coefficient = ', F
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Planetographic coordinates:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' Longitude (deg) = ', LON / RPD()
/// WRITE(*,*) ' Latitude (deg) = ', LAT / RPD()
/// WRITE(*,*) ' Altitude (km) = ', ALT
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Planetographic velocity:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' d Longitude/dt (deg/s) = ', PGRVEL(1)/RPD()
/// WRITE(*,*) ' d Latitude/dt (deg/s) = ', PGRVEL(2)/RPD()
/// WRITE(*,*) ' d Altitude/dt (km/s) = ', PGRVEL(3)
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Rectangular coordinates from inverse ' //
/// . 'mapping:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' X (km) = ', RECTAN(1)
/// WRITE(*,*) ' Y (km) = ', RECTAN(2)
/// WRITE(*,*) ' Z (km) = ', RECTAN(3)
/// WRITE(*,*) ' '
/// WRITE(*,*) 'Rectangular velocity from inverse mapping:'
/// WRITE(*,*) ' '
/// WRITE(*,*) ' dX/dt (km/s) = ', DRECTN(1)
/// WRITE(*,*) ' dY/dt (km/s) = ', DRECTN(2)
/// WRITE(*,*) ' dZ/dt (km/s) = ', DRECTN(3)
/// WRITE(*,*) ' '
/// END
///
///
/// When this program was executed on a Mac/Intel/gfortran/64-bit
/// platform, the output was:
///
///
/// Rectangular coordinates:
///
/// X (km) = 146039733.67043769
/// Y (km) = 278546605.40670651
/// Z (km) = 119750317.58721757
///
/// Rectangular velocity:
///
/// dX/dt (km/s) = -47.043272004450600
/// dY/dt (km/s) = 9.0732615496727291
/// dZ/dt (km/s) = 4.7579169009979010
///
/// Ellipsoid shape parameters:
///
/// Equatorial radius (km) = 3396.1900000000001
/// Polar radius (km) = 3376.1999999999998
/// Flattening coefficient = 5.8860075555255261E-003
///
/// Planetographic coordinates:
///
/// Longitude (deg) = 297.66765938292673
/// Latitude (deg) = 20.844504443932596
/// Altitude (km) = 336531825.52621418
///
/// Planetographic velocity:
///
/// d Longitude/dt (deg/s) = -8.3577066632519065E-006
/// d Latitude/dt (deg/s) = 1.5935566850478802E-006
/// d Altitude/dt (km/s) = -11.211600779360412
///
/// Rectangular coordinates from inverse mapping:
///
/// X (km) = 146039733.67043760
/// Y (km) = 278546605.40670651
/// Z (km) = 119750317.58721757
///
/// Rectangular velocity from inverse mapping:
///
/// dX/dt (km/s) = -47.043272004450600
/// dY/dt (km/s) = 9.0732615496727167
/// dZ/dt (km/s) = 4.7579169009978992
/// ```
///
/// # Author and Institution
///
/// ```text
/// N.J. Bachman (JPL)
/// J. Diaz del Rio (ODC Space)
/// B.V. Semenov (JPL)
/// W.L. Taber (JPL)
/// ```
///
/// # Version
///
/// ```text
/// - SPICELIB Version 1.1.1, 12-AUG-2021 (JDR)
///
/// Edited the header to comply with NAIF standard.
/// Modified code example to use meta-kernel to load kernels.
///
/// - SPICELIB Version 1.1.0, 21-SEP-2013 (BVS)
///
/// Updated to save the input body name and ZZBODTRN state counter
/// and to do name-ID conversion only if the counter has changed.
///
/// Updated to call LJUCRS instead of CMPRSS/UCASE.
///
/// - SPICELIB Version 1.0.0, 26-DEC-2004 (NJB) (WLT)
/// ```
pub fn dpgrdr(
ctx: &mut SpiceContext,
body: &str,
x: f64,
y: f64,
z: f64,
re: f64,
f: f64,
jacobi: &mut [[f64; 3]; 3],
) -> crate::Result<()> {
DPGRDR(
body.as_bytes(),
x,
y,
z,
re,
f,
jacobi.as_flattened_mut(),
ctx.raw_context(),
)?;
ctx.handle_errors()?;
Ok(())
}
//$Procedure DPGRDR ( Derivative of planetographic w.r.t. rectangular )
pub fn DPGRDR(
BODY: &[u8],
X: f64,
Y: f64,
Z: f64,
RE: f64,
F: f64,
JACOBI: &mut [f64],
ctx: &mut Context,
) -> f2rust_std::Result<()> {
let save = ctx.get_vars::<SaveVars>();
let save = &mut *save.borrow_mut();
let mut JACOBI = DummyArrayMut2D::new(JACOBI, 1..=3, 1..=3);
let mut KVALUE = [b' '; LNSIZE as usize];
let mut PMKVAR = [b' '; KVNMLN as usize];
let mut PGRLON = [b' '; SENSLN as usize];
let mut BODYID: i32 = 0;
let mut N: i32 = 0;
let mut SENSE: i32 = 0;
let mut FOUND: bool = false;
//
// SPICELIB functions
//
//
// Local parameters
//
//
// Saved body name length.
//
//
// Local variables
//
//
// Saved name/ID item declarations.
//
//
// Saved name/ID items.
//
//
// Initial values.
//
//
// Standard SPICE error handling.
//
if RETURN(ctx) {
return Ok(());
} else {
CHKIN(b"DPGRDR", ctx)?;
}
//
// Initialization.
//
if save.FIRST {
//
// Initialize counter.
//
ZZCTRUIN(save.SVCTR1.as_slice_mut(), ctx);
save.FIRST = false;
}
//
// Convert the body name to an ID code.
//
ZZBODS2C(
save.SVCTR1.as_slice_mut(),
&mut save.SVBODY,
&mut save.SVBDID,
&mut save.SVFND1,
BODY,
&mut BODYID,
&mut FOUND,
ctx,
)?;
if !FOUND {
SETMSG(b"The value of the input argument BODY is #, this is not a recognized name of an ephemeris object. The cause of this problem may be that you need an updated version of the SPICE Toolkit. ", ctx);
ERRCH(b"#", BODY, ctx);
SIGERR(b"SPICE(IDCODENOTFOUND)", ctx)?;
CHKOUT(b"DPGRDR", ctx)?;
return Ok(());
}
//
// The equatorial radius must be positive. If not, signal an error
// and check out.
//
if (RE <= 0.0) {
SETMSG(b"Equatorial radius was #.", ctx);
ERRDP(b"#", RE, ctx);
SIGERR(b"SPICE(VALUEOUTOFRANGE)", ctx)?;
CHKOUT(b"DPGRDR", ctx)?;
return Ok(());
}
//
// If the flattening coefficient is greater than 1, the polar radius
// is negative. If F is equal to 1, the polar radius is zero. Either
// case is a problem, so signal an error and check out.
//
if (F >= 1.0) {
SETMSG(b"Flattening coefficient was #.", ctx);
ERRDP(b"#", F, ctx);
SIGERR(b"SPICE(VALUEOUTOFRANGE)", ctx)?;
CHKOUT(b"DPGRDR", ctx)?;
return Ok(());
}
//
// Look up the longitude sense override variable from the
// kernel pool.
//
REPMI(OVRTMP, b"#", BODYID, &mut PMKVAR, ctx);
GCPOOL(
&PMKVAR,
1,
1,
&mut N,
CharArrayMut::from_mut(&mut KVALUE),
&mut FOUND,
ctx,
)?;
if FOUND {
//
// Make sure we recognize the value of PGRLON.
//
LJUCRS(0, &KVALUE, &mut PGRLON, ctx);
if fstr::eq(&PGRLON, b"EAST") {
SENSE = 1;
} else if fstr::eq(&PGRLON, b"WEST") {
SENSE = -1;
} else {
SETMSG(
b"Kernel variable # may have the values EAST or WEST. Actual value was #.",
ctx,
);
ERRCH(b"#", &PMKVAR, ctx);
ERRCH(b"#", &KVALUE, ctx);
SIGERR(b"SPICE(INVALIDOPTION)", ctx)?;
CHKOUT(b"DPGRDR", ctx)?;
return Ok(());
}
} else {
//
// Look up the spin sense of the body's prime meridian.
//
SENSE = PLNSNS(BODYID, ctx)?;
//
// If the required prime meridian rate was not available,
// PLNSNS returns the code 0. Here we consider this situation
// to be an error.
//
if (SENSE == 0) {
REPMI(PMTMP, b"#", BODYID, &mut PMKVAR, ctx);
SETMSG(b"Prime meridian rate coefficient defined by kernel variable # is required but not available for body #. ", ctx);
ERRCH(b"#", &PMKVAR, ctx);
ERRCH(b"#", BODY, ctx);
SIGERR(b"SPICE(MISSINGDATA)", ctx)?;
CHKOUT(b"DPGRDR", ctx)?;
return Ok(());
}
//
// Handle the special cases: earth, moon, and sun.
//
if (((BODYID == EARTH) || (BODYID == MOON)) || (BODYID == SUN)) {
SENSE = 1;
}
}
//
// At this point, SENSE is set to +/- 1.
//
// To obtain the Jacobian matrix we want, first find the Jacobian
// matrix of rectangular coordinates with respect to geodetic
// coordinates.
//
DGEODR(X, Y, Z, RE, F, JACOBI.as_slice_mut(), ctx)?;
//
// Letting GLON represent geodetic longitude, the matrix JACOBI is
//
// .- -.
// | DGLON/DX DGLON/DY DGLON/DZ |
// | DLAT/DX DLAT/DY DLAT/DZ |
// | DALT/DX DALT/DY DALT/DZ |
// `- -'
//
// evaluated at the input values of X, Y, and Z.
//
// Since planetographic longitude LON satisfies
//
// LON = SENSE * GLON
//
// applying the chain rule to D(*)/DGLON, the above is equivalent to
//
// .- -.
// | (1/SENSE)*DLON/DX (1/SENSE)*DLON/DY (1/SENSE)*DLON/DZ |
// | DLAT/DX DLAT/DY DLAT/DZ |
// | DALT/DX DALT/DY DALT/DZ |
// `- -'
//
// So, multiplying the first row of JACOBI by SENSE gives us the
// matrix we actually want to compute: the Jacobian matrix of
// rectangular coordinates with respect to planetographic
// coordinates.
//
for I in 1..=3 {
JACOBI[[1, I]] = ((SENSE as f64) * JACOBI[[1, I]]);
}
CHKOUT(b"DPGRDR", ctx)?;
Ok(())
}