% @(#)computrow.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:43:22 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      computrow.hlq
%.AUTHOR     KB, IPG/ESO
%.KEYWORDS   MIDAS, help files, COMPUTE/ROW
%.PURPOSE    On-line help file for the command: COMPUTE/ROW
%.VERSION    1.0  02-NOV-1983 : Creation, KB
%----------------------------------------------------------------
\se
SECTION./ROW
\es\co
COMPUTE/ROW						 06-DEC-1994  KB
\oc\su
COMPUTE/ROW res_frame.row = arithmetic_expression
	do arithmetics on rows (lines) of images
\us\pu
Purpose:
          Perform arithmetic operations on rows of images and store result
          in a row of an image.
\up\sy
Syntax:  
          COMPUTE/ROW res_frame.row = expression
\ys\pa
          res_frame.row = image and row to get result of expression,
              the row is specified by Ri (or ri), with i in [1,NPIX(2)];
\\
              if VMS, a new version of the frame will be created by MIDAS
\ap\pa
          expression = expression with up to 10 operands, which may be
              functions and rows or/and constants in the usual algebraic
              notation, rows of the res_frame are indicated by a leading 
              "R" or "r";
\\
              rows of other frames are indicated via `frame.Ri'
\ap\no
Note: 
          The operations +, -, *, / and ** are supported with the same
          precedence as in FORTRAN. Parentheses may be used to change that
          order as well as to nest operations.
\\
          The functions SQRT(a), EXP(a), EXP10(a), LN(a), LOG10(a), SIN(a)
          ASIN(a), COS(a), ACOS(a), TAN(a), ATAN(a), INT(a), ATAN2(a1,a2),
          MAX(a1,a2), MIN(a1,a2), MOD(a1,a2) and ABS(a), are implemented as in
          FORTRAN. Except that INT(a) will return the nearest integer of "a"
          converted to real.
\\
          The trigonometric functions expect arguments in degrees!
\\
          Results of illegal operations (e.g. division by zero) are set to
          the "null value" defined by the keyword NULL.
\\
          If rows from other frames are involved in the expression, they
          must have the same no. of pixels per row, i.e. NPIX(1). The no. of
          rows does not have to be the same, i.e. you can mix 1-dim and
          2-dim frames.
\on\see
See also:
          COMPUTE/COLUMN, COMPUTE/PLANE, COMPUTE/IMAGE
\ees\exs
Examples:
\ex
          COMPUTE/ROW tiburon.R22 = R100+R44
            Use image frame tiburon.bdf and add the 100th row to the 44th row,
            store the result into the 22nd row of frame tiburon.bdf .
\xe\ex
          COMPUTE/ROW ballena.r7 = 99.9*sin(delfin.r125)
            Set the 7th row of frame ballena.bdf to the product of 99.9 and
            the sine of the contents of row no. 125 of frame delfin.bdf . The
            no. of pixels per row of ballena.bdf and delfin.bdf must be equal.
\xe\ex
          COMPUTE/ROW ballena.r2 = 2.*r27
            Compute 2.0 * 27th row of ballena.bdf and store result into second
            row of frame ballena.bdf .
\xe \sxe