Procedure

   SpiceDouble dpmax_c () 

Abstract

 
   Return the value of the largest (positive) number representable 
   in a double precision variable. 
 

Required_Reading

 
   None. 
 

Keywords

 
   CONSTANTS 
 

Brief_I/O

 
   The function returns the value of the largest (positive) number 
   that can be represented in a double precision variable. 
 

Detailed_Input

 
   None. 
 

Detailed_Output

 
   The function returns the value of the largest (positive) number 
   that can be represented in a double precision variable. 
 
   This value varies from machine to machine.  The value is defined by 
   the macro DBL_MAX from the ANSI standard header file float.h.
   According to the ANSI standard, DBL_MAX must be at least
   
      1.E+37 
         
 

Parameters

 
   None. 
 

Exceptions

 
   Error free. 
 

Files

 
   None. 
 

Particulars

 
   The function always returns a constant value, set by the user 
   prior to compilation. 
 

Examples

 
   The following code fragments illustrate the use of dpmax_c. 
   Note in the second example that the smallest negative number 
   is not necessarily the negative of the largest positive number. 
 
   1) Set a range variable for a star or ephemeris object.
      
      /.
      Compute the distance to each object. For stars, use 
      a "very large" distance. 
      ./
      
      for ( i = 0;  i < n;  i++ )
      {
         if (  strcmp ( type[i], "star" )  ) 
         {
            /.
            The object is not a star.
            ./
            
            range[i] = vnorm_c ( state[i] );
         }
         else 
         {
            range[i] = sqrt ( dpmax_c() ) / 2.;
         }
      }



   2) Initialize a CSPICE "window."
   
      /.
      The window originally has one interval, from "minus 
      infinity" to "plus infinity". 
      ./
      
      winsiz    =  2;
      window[0] =  dpmin_c();
      window[1] =  dpmax_c() ;

      scardd_ ( &winsiz, window ); 
      
 

Restrictions

 
   None. 
 

Literature_References

 
   None.
    

Author_and_Institution

 
   N.J. Bachman    (JPL) 
   H.A. Neilan     (JPL) 
   M.J. Spencer    (JPL) 
   W.L. Taber      (JPL) 
   I.M. Underwood  (JPL) 
 

Version

 
   -CSPICE Version 1.1.0, 23-JUL-2001 (NJB)
     
      Removed tab characters from source file.

   -CSPICE Version 1.0.0, 16-OCT-1998 (NJB)

Index_Entries

 
   largest d.p. number 
 

Link to routine dpmax_c source file dpmax_c.c