GEO_vec_length3.c

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/* file: GEO_vec_length3.c */
 
#include "GEO_basic.h"
#include "GEO_util.h"
 
void GEO_vec_length3(
    double vec[3],
    double * const length
        )
{
/*
!C*****************************************************************************
!Description:   subroutine in the utility functions of the Level-1A geolocation
                software to calculate the length of a 3 element vector.
 
!Input Parameters:
        double vec - a three element vector
 
!Output Parameters:
        double *length - the length of the three element vector
 
!Revision History:
        $Log: GEO_vec_length3.c,v $
        Revision 1.4  1997/07/21 16:24:34  kuyper
        Baselined Version 1
 
 * Revision 1.4  1997/03/26  18:16:39  fhliang
 * Initial revision of SDST delivery of GEO_vec_length3.c.
 *
        Revision 1.3  1996/07/24 21:47:10  kuyper
        Changed to return void.
        Declared arguments const.
        Inserted required '!'s in comments.
        Converted constants to double, to skip implied conversion.
 
        Revision 1.2  1996/07/18 21:25:35  kuyper
        Included self-checking header file.
 
 
        4/5/95
        Ruiming Chen
        Finished coding.
 
        6/12/95
        Frederick S. Patt (patt@modis-xl.gsfc.nasa.gov)
        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*************************************************************************
*/
 
  int i = 0;  /* iteration parameter */
 
  *length = 0.0;
  for (i = 0; i < 3; ++i)
    *length = *length + vec[i] * vec[i];
 
  *length = sqrt(*length);
 
 
  return;
}