GEO_poly_coef1.c

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#include "GEO_basic.h"
#include "GEO_util.h"
 
int GEO_poly_coef1(
    double const var_val1,
    double const var_val2,
    double const derivative1,
    double const derivative2,
    double const t1,
    double const t2,
    double fit_coef[CUBIC])
 
/*
!C*****************************************************************************
!Description:   
        subroutine in utility group of the Level-1A geolocation
                software to generate cubic polynomial coefficients using
        values and slopes at two times.
 
!Input Parameters:
                double var_val1 - value of first point
            double var_val2 - value of second point
            double derivative1 - slope of first point
            double derivative2 - slope of second point
            double t1 - time of first point
            double t2 - time of second point
                int scan_number - the scan number
 
!Output Parameters:
                double fit_coef[CUBIC] - cubic polynomial coefficients
 
Return parameter:
                int err_stat - error status
 
Global variables:
            None
 
Call functions:
        None
 
!Revision History:
 * $Log: GEO_poly_coef1.c,v $
 * Revision 2.1  1997/10/21 18:16:22  kuyper
 * Returned from ClearCase
 *
 * Revision /main/GEO_V2_DEV/1 1997/10/15 kuyper
 * Changed to use CUBIC macro.
 *
 * Revision 1.5  1997/07/21  16:24:34  kuyper
 * Baselined Version 1
 *
 * Revision 1.5  1997/03/26  18:10:35  fhliang
 * Initial revision of SDST delivery of GEO_poly_coef1.c.
 *
        Revision 1.4  1996/07/24 21:08:47  kuyper
        Declared arguments const.
 
        Revision 1.3  1996/07/23 23:29:41  kuyper
        Inserted required '!'s in comments.
        Changed constants to double, to avoid conversions.
 
        Revision 1.2  1996/07/18 19:52:42  kuyper
        Included self-checking header file.
 
 
        6/2/95
        Frederick S. Patt (patt@modis-xl.gsfc.nasa.gov)
        Finished coding.
 
        6/12/95
        Frederick S. Patt
        Revised prolog
 
!Team-unique Header:
                This software is developed by the MODIS Science Data Support
                Team for the National Aeronautics and Space Administration,
                Goddard Space Flight Center, under contract NAS5-32373.
 
!END*************************************************************************
*/
 
{
/* Local variable declarations */
 
  double dt = 1.0;
 
  /* Begin program logic */
 
  dt = t2 - t1;
 
  /* calculate the polynominal coefficients */
  fit_coef[0] = var_val1;
  fit_coef[1] = derivative1*dt;
  fit_coef[2] = 3.0*var_val2 - 3.0*var_val1 - 2.0*derivative1*dt -
      derivative2*dt;
  fit_coef[3] = 2.0*var_val1 - 2.0*var_val2 + derivative1*dt + derivative2*dt;
 
  return SUCCESS;
}