rfa 0.5.9

use crate::{rfam::*, utils::*};
use crate::fundamental_args::{fal03::*, faf03::*, falp03::*, fave03::*, fapa03::*, fad03::*, faom03::*, fae03::*, };

/*
**  - - - - - - -
**   e r a S 0 6
**  - - - - - - -
**
**  The CIO locator s, positioning the Celestial Intermediate Origin on
**  the equator of the Celestial Intermediate Pole, given the CIP's X,Y
**  coordinates.  Compatible with IAU 2006/2000A precession-nutation.
**
**  Given:
**     date1,date2   double    TT as a 2-part Julian Date (Note 1)
**     x,y           double    CIP coordinates (Note 3)
**
**  Returned (function value):
**                   double    the CIO locator s in radians (Note 2)
**
**  Notes:
**
**  1) The TT date date1+date2 is a Julian Date, apportioned in any
**     convenient way between the two arguments.  For example,
**     JD(TT)=2450123.7 could be expressed in any of these ways,
**     among others:
**
**            date1          date2
**
**         2450123.7           0.0       (JD method)
**         2451545.0       -1421.3       (J2000 method)
**         2400000.5       50123.2       (MJD method)
**         2450123.5           0.2       (date & time method)
**
**     The JD method is the most natural and convenient to use in
**     cases where the loss of several decimal digits of resolution
**     is acceptable.  The J2000 method is best matched to the way
**     the argument is handled internally and will deliver the
**     optimum resolution.  The MJD method and the date & time methods
**     are both good compromises between resolution and convenience.
**
**  2) The CIO locator s is the difference between the right ascensions
**     of the same point in two systems:  the two systems are the GCRS
**     and the CIP,CIO, and the point is the ascending node of the
**     CIP equator.  The quantity s remains below 0.1 arcsecond
**     throughout 1900-2100.
**
**  3) The series used to compute s is in fact for s+XY/2, where X and Y
**     are the x and y components of the CIP unit vector;  this series
**     is more compact than a direct series for s would be.  This
**     function requires X,Y to be supplied by the caller, who is
**     responsible for providing values that are consistent with the
**     supplied date.
**
**  4) The model is consistent with the "P03" precession (Capitaine et
**     al. 2003), adopted by IAU 2006 Resolution 1, 2006, and the
**     IAU 2000A nutation (with P03 adjustments).
**
**  Called:
**     eraFal03     mean anomaly of the Moon
**     eraFalp03    mean anomaly of the Sun
**     eraFaf03     mean argument of the latitude of the Moon
**     eraFad03     mean elongation of the Moon from the Sun
**     eraFaom03    mean longitude of the Moon's ascending node
**     eraFave03    mean longitude of Venus
**     eraFae03     mean longitude of Earth
**     eraFapa03    general accumulated precession in longitude
**
**  References:
**
**     Capitaine, N., Wallace, P.T. & Chapront, J., 2003, Astron.
**     Astrophys. 432, 355
**
**     McCarthy, D.D., Petit, G. (eds.) 2004, IERS Conventions (2003),
**     IERS Technical Note No. 32, BKG
**
**  This revision:  2021 May 11
**
**  Copyright (C) 2013-2021, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/
pub fn s06(date1: f64, date2: f64, x: f64, y: f64)->f64
{
    /* Fundamental arguments */
        let mut fa = [0.0; 8];
    
    /* --------------------- */
    /* The series for s+XY/2 */
    /* --------------------- */
    
        struct TERM {
            nfa: [i32; 8],      /* coefficients of l,l',F,D,Om,LVe,LE,pA */
            s: f64, c: f64,      /* sine and cosine coefficients */
        }
        impl TERM {
            pub const fn new (nfa: [i32; 8], s: f64, c: f64,) ->Self{
                TERM { nfa: nfa, s: s, c: c }
            }
        } 
    
    /* Polynomial coefficients */
        const SP: [f64; 6] = [

    
       /* 1-6 */
              94.00e-6,
            3808.65e-6,
            -122.68e-6,
          -72574.11e-6,
              27.98e-6,
              15.62e-6
        ];
    
    /* Terms of order t^0 */
       const S0: [TERM;33] = [
    
       /* 1-10 */
TERM::new([0,  0,  0,  0,  1,  0,  0,  0], -2640.73e-6,   0.39e-6 ), 
TERM::new([0,  0,  0,  0,  2,  0,  0,  0],   -63.53e-6,   0.02e-6 ), 
TERM::new([0,  0,  2, -2,  3,  0,  0,  0],   -11.75e-6,  -0.01e-6 ), 
TERM::new([0,  0,  2, -2,  1,  0,  0,  0],   -11.21e-6,  -0.01e-6 ), 
TERM::new([0,  0,  2, -2,  2,  0,  0,  0],     4.57e-6,   0.00e-6 ), 
TERM::new([0,  0,  2,  0,  3,  0,  0,  0],    -2.02e-6,   0.00e-6 ), 
TERM::new([0,  0,  2,  0,  1,  0,  0,  0],    -1.98e-6,   0.00e-6 ), 
TERM::new([0,  0,  0,  0,  3,  0,  0,  0],     1.72e-6,   0.00e-6 ), 
TERM::new([0,  1,  0,  0,  1,  0,  0,  0],     1.41e-6,   0.01e-6 ), 
TERM::new([0,  1,  0,  0, -1,  0,  0,  0],     1.26e-6,   0.01e-6 ), 
    
       /* 11-20 */
TERM::new([1,  0,  0,  0, -1,  0,  0,  0],     0.63e-6,   0.00e-6 ), 
TERM::new([1,  0,  0,  0,  1,  0,  0,  0],     0.63e-6,   0.00e-6 ), 
TERM::new([0,  1,  2, -2,  3,  0,  0,  0],    -0.46e-6,   0.00e-6 ), 
TERM::new([0,  1,  2, -2,  1,  0,  0,  0],    -0.45e-6,   0.00e-6 ), 
TERM::new([0,  0,  4, -4,  4,  0,  0,  0],    -0.36e-6,   0.00e-6 ), 
TERM::new([0,  0,  1, -1,  1, -8, 12,  0],     0.24e-6,   0.12e-6 ), 
TERM::new([0,  0,  2,  0,  0,  0,  0,  0],    -0.32e-6,   0.00e-6 ), 
TERM::new([0,  0,  2,  0,  2,  0,  0,  0],    -0.28e-6,   0.00e-6 ), 
TERM::new([1,  0,  2,  0,  3,  0,  0,  0],    -0.27e-6,   0.00e-6 ), 
TERM::new([1,  0,  2,  0,  1,  0,  0,  0],    -0.26e-6,   0.00e-6 ), 
    
       /* 21-30 */
TERM::new([0,  0,  2, -2,  0,  0,  0,  0],     0.21e-6,   0.00e-6 ), 
TERM::new([0,  1, -2,  2, -3,  0,  0,  0],    -0.19e-6,   0.00e-6 ), 
TERM::new([0,  1, -2,  2, -1,  0,  0,  0],    -0.18e-6,   0.00e-6 ), 
TERM::new([0,  0,  0,  0,  0,  8,-13, -1],     0.10e-6,  -0.05e-6 ), 
TERM::new([0,  0,  0,  2,  0,  0,  0,  0],    -0.15e-6,   0.00e-6 ), 
TERM::new([2,  0, -2,  0, -1,  0,  0,  0],     0.14e-6,   0.00e-6 ), 
TERM::new([0,  1,  2, -2,  2,  0,  0,  0],     0.14e-6,   0.00e-6 ), 
TERM::new([1,  0,  0, -2,  1,  0,  0,  0],    -0.14e-6,   0.00e-6 ), 
TERM::new([1,  0,  0, -2, -1,  0,  0,  0],    -0.14e-6,   0.00e-6 ), 
TERM::new([0,  0,  4, -2,  4,  0,  0,  0],    -0.13e-6,   0.00e-6 ), 
    
       /* 31-33 */
TERM::new([0,  0,  2, -2,  4,  0,  0,  0],     0.11e-6,   0.00e-6 ), 
TERM::new([1,  0, -2,  0, -3,  0,  0,  0],    -0.11e-6,   0.00e-6 ), 
TERM::new([1,  0, -2,  0, -1,  0,  0,  0],    -0.11e-6,   0.00e-6 )
       ];
    
    /* Terms of order t^1 */
       const S1: [TERM; 3] = [
    
       /* 1 - 3 */
TERM::new([0,  0,  0,  0,  2,  0,  0,  0],    -0.07e-6,   3.57e-6 ), 
TERM::new([0,  0,  0,  0,  1,  0,  0,  0],     1.73e-6,  -0.03e-6 ), 
TERM::new([0,  0,  2, -2,  3,  0,  0,  0],     0.00e-6,   0.48e-6 )
       ];
    
    /* Terms of order t^2 */
       const S2: [TERM; 25] = [
    
       /* 1-10 */
TERM::new([0,  0,  0,  0,  1,  0,  0,  0],   743.52e-6,  -0.17e-6 ), 
TERM::new([0,  0,  2, -2,  2,  0,  0,  0],    56.91e-6,   0.06e-6 ), 
TERM::new([0,  0,  2,  0,  2,  0,  0,  0],     9.84e-6,  -0.01e-6 ), 
TERM::new([0,  0,  0,  0,  2,  0,  0,  0],    -8.85e-6,   0.01e-6 ), 
TERM::new([0,  1,  0,  0,  0,  0,  0,  0],    -6.38e-6,  -0.05e-6 ), 
TERM::new([1,  0,  0,  0,  0,  0,  0,  0],    -3.07e-6,   0.00e-6 ), 
TERM::new([0,  1,  2, -2,  2,  0,  0,  0],     2.23e-6,   0.00e-6 ), 
TERM::new([0,  0,  2,  0,  1,  0,  0,  0],     1.67e-6,   0.00e-6 ), 
TERM::new([1,  0,  2,  0,  2,  0,  0,  0],     1.30e-6,   0.00e-6 ), 
TERM::new([0,  1, -2,  2, -2,  0,  0,  0],     0.93e-6,   0.00e-6 ), 
    
       /* 11-20 */
TERM::new([1,  0,  0, -2,  0,  0,  0,  0],     0.68e-6,   0.00e-6 ), 
TERM::new([0,  0,  2, -2,  1,  0,  0,  0],    -0.55e-6,   0.00e-6 ), 
TERM::new([1,  0, -2,  0, -2,  0,  0,  0],     0.53e-6,   0.00e-6 ), 
TERM::new([0,  0,  0,  2,  0,  0,  0,  0],    -0.27e-6,   0.00e-6 ), 
TERM::new([1,  0,  0,  0,  1,  0,  0,  0],    -0.27e-6,   0.00e-6 ), 
TERM::new([1,  0, -2, -2, -2,  0,  0,  0],    -0.26e-6,   0.00e-6 ), 
TERM::new([1,  0,  0,  0, -1,  0,  0,  0],    -0.25e-6,   0.00e-6 ), 
TERM::new([1,  0,  2,  0,  1,  0,  0,  0],     0.22e-6,   0.00e-6 ), 
TERM::new([2,  0,  0, -2,  0,  0,  0,  0],    -0.21e-6,   0.00e-6 ), 
TERM::new([2,  0, -2,  0, -1,  0,  0,  0],     0.20e-6,   0.00e-6 ), 
    
       /* 21-25 */
TERM::new([0,  0,  2,  2,  2,  0,  0,  0],     0.17e-6,   0.00e-6 ), 
TERM::new([2,  0,  2,  0,  2,  0,  0,  0],     0.13e-6,   0.00e-6 ), 
TERM::new([2,  0,  0,  0,  0,  0,  0,  0],    -0.13e-6,   0.00e-6 ), 
TERM::new([1,  0,  2, -2,  2,  0,  0,  0],    -0.12e-6,   0.00e-6 ), 
TERM::new([0,  0,  2,  0,  0,  0,  0,  0],    -0.11e-6,   0.00e-6 )
       ];
    
    /* Terms of order t^3 */
       const S3: [TERM; 4] = [
    
       /* 1-4 */
TERM::new([0,  0,  0,  0,  1,  0,  0,  0],     0.30e-6, -23.42e-6 ), 
TERM::new([0,  0,  2, -2,  2,  0,  0,  0],    -0.03e-6,  -1.46e-6 ), 
TERM::new([0,  0,  2,  0,  2,  0,  0,  0],    -0.01e-6,  -0.25e-6 ), 
TERM::new([0,  0,  0,  0,  2,  0,  0,  0],     0.00e-6,   0.23e-6 )
       ];
    
    /* Terms of order t^4 */
       const S4: [TERM; 1] = [
    
       /* 1-1 */
TERM::new([0,  0,  0,  0,  1,  0,  0,  0],    -0.26e-6,  -0.01e-6 )
       ];
    
/* Interval between fundamental epoch J2000.0 and current date (JC). */
let t = ((date1 - URSA_DJ00) + date2) / URSA_DJC;

/* Fundamental Arguments (from IERS Conventions 2003) */

/* Mean anomaly of the Moon. */
   fa[0] = fal03(t);

/* Mean anomaly of the Sun. */
   fa[1] = falp03(t);

/* Mean longitude of the Moon minus that of the ascending node. */
   fa[2] = faf03(t);

/* Mean elongation of the Moon from the Sun. */
   fa[3] = fad03(t);

/* Mean longitude of the ascending node of the Moon. */
   fa[4] = faom03(t);

/* Mean longitude of Venus. */
   fa[5] = fave03(t);

/* Mean longitude of Earth. */
   fa[6] = fae03(t);

/* General precession in longitude. */
   fa[7] = fapa03(t);

/* Evaluate s. */
   let mut w0 = SP[0];
   let mut w1 = SP[1];
   let mut w2 = SP[2];
   let mut w3 = SP[3];
   let mut w4 = SP[4];
   let  w5 = SP[5];

   for s0_i in S0.iter() {
      let mut a = 0.0;
      for j in 0..8 {
          a += s0_i.nfa[j] as f64 * fa[j];
      }
      w0 += s0_i.s * sin(a) + s0_i.c * cos(a);
   }

   for s1_i in S1.iter() {
      let mut a = 0.0;
      for j in 0..8 {
          a += s1_i.nfa[j] as f64 * fa[j];
      }
      w1 += s1_i.s * sin(a) + s1_i.c * cos(a);
   }

   for s2_i in S2.iter() {
      let mut a = 0.0;
      for j in 0..8 {
          a += s2_i.nfa[j] as f64 * fa[j];
      }
      w2 += s2_i.s * sin(a) + s2_i.c * cos(a);
   }

   for s3_i in S3.iter() {
      let mut a = 0.0;
      for j in 0..8 {
          a += s3_i.nfa[j] as f64 * fa[j];
      }
      w3 += s3_i.s * sin(a) + s3_i.c * cos(a);
   }

   for s4_i in S4.iter() {
    let mut a = 0.0;
      for j in 0..8 {
          a += s4_i.nfa[j] as f64 * fa[j];
      }
      w4 += s4_i.s * sin(a) + s4_i.c * cos(a);
   }

       (w0 +
       (w1 +
       (w2 +
       (w3 +
       (w4 +
        w5 * t) * t) * t) * t) * t) * URSA_DAS2R - x*y/2.0
    
    /* Finished. */
    
}