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			       AR

      ARITHMETIC is a module which performs image arithmetic.  It accepts
 as input an arithmetic expression, parses it and applies it to a set
 of input maps, leaving the result in a set of output maps.  Because of the
 considerable power of the program, scope exists for the user to corrupt or
 delete data.  Please exercise care in using this option;  check your
 expressions before pressing <CR>.
      The  program  prompts the user to enter the arithmetic expression:

               Enter expression to be evaluated
               Expression=

 A <CR> at this stage will cause ARITHMETIC to return to the main program.
 A simple example of this routine is given below.  Occasionaly, it will be
 more convenient to use option AT or one of the other more specialized
 arithmetic options when looping is desired.

 The operation below converts magnitudes to relative intensities.

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 Enter an option:                              26-SEP-1981 17:51:29.09
 OPTION=AR
  
 Enter the expression to be evaluated:
 Expression=EXCUT<1>=0-0.4*EXCUT<1>  
			    ....The 0 is necessary to negate the values
  
 The file EXCUT is used in the expression                                      
 There are   2 maps in the file       
 Reading from the file
   11 rows of 2035 pixels in R4 format
  
 Opening file EXCUT for output                                                 
 Writing to an existing file
   11 rows of 2035 pixels in R4 format
  
 Do you wish to evaluate another expression?  (default = N)
 MORE=Y

 Enter the expression to be evaluated:
 Expression=EXCUT<1>=10**EXCUT<1>
					    ....Antilog
  
 The file EXCUT is used in the expression                                      
 There are   2 maps in the file       
 Reading from the file
   11 rows of 2035 pixels in R4 format
  
 Opening file EXCUT for output                                                 
 Writing to an existing file
   11 rows of 2035 pixels in R4 format
  
 Do you wish to evaluate another expression?  (default = N)
 MORE=
 F
 Enter an option:                              26-SEP-1981 17:52:19.09
 OPTION=
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