GEO_vec_prod3.c

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/* GEO_vec_prod3.c */
 
#include "GEO_basic.h"
#include "GEO_util.h"
 
void GEO_vec_prod3(
    double  vec1[3],
    double  vec2[3],
    double  * const prod
        )
{
/*
!C*****************************************************************************
!Description:   subroutine in the utility functions of the Level-1A geolocation
                software to calculate the products of two 3 element vectors.
 
!Input Parameters:
        double vec1[3] - the first 3 element vector
        doubel vec2[3] - the second 3 element vector
 
!Output Parameters:
        double *prod - the product of the two input 3 element vectors
 
!Revision History:
        $Log: GEO_vec_prod3.c,v $
        Revision 1.4  1997/07/21 16:24:34  kuyper
        Baselined Version 1
 
 * Revision 1.4  1997/03/26  18:17:00  fhliang
 * Initial revision of SDST delivery of GEO_vec_prod3.c.
 *
        Revision 1.3  1996/07/24 21:52:58  kuyper
        Changed to return void.
        Declared arguments const.
        Inserted required '!'s in comments.
        Converted constants to double, to skip implied conversion.
        Removed ret_val.
 
        Revision 1.2  1996/07/18 21:27:33  kuyper
        Included self-checking header file.
 
 
        4/5/95
        Ruiming Chen (rchen@ltpmail.gsfc.nasa.gov)
        Finished coding.
 
        6/12/95
        Frederick S. Patt (patt@modis-xl.gsfc.nasa.gov)
        Revised prolog
 
Call function:
        None
 
!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 */
 
  /* calculate the product of vec1 and vec2 */  
  *prod = 0.0;
  for (i = 0; i < 3; ++i)
    *prod = *prod + vec1[i] * vec2[i];
 
  return;
}