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% @(#)computcolu.hlq 19.1 (ESO-IPG) 02/25/03 14:03:02
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%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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%.COPYRIGHT (c) 1990 European Southern Observatory
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%.KEYWORDS MIDAS, help files, COMPUTE/COLUMN
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%.PURPOSE On-line help file for the command: COMPUTE/COLUMN
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%.VERSION 1.0 01-JUN-1987 : Creation, KB
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%----------------------------------------------------------------
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COMPUTE/COLUMN 06-DEC-1994 KB
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COMPUTE/COLUMN res_frame.column = arithmetic_expression
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do arithmetics on columns of an image
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Perform arithmetic operations on columns of images and store result
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in a column of an image.
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COMPUTE/COLUMN res_frame.column = expression
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res_frame.column = \\ image and column to get result of expression,
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the column is specified by Ci (or ci), with i in [1,NPIX(1)];
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if VMS, a new version of the frame will be created by MIDAS
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expression = expression with up to 10 operands, which may be
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functions and columns or/and constants in the usual algebraic
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notation, columns of the res_frame are indicated by a leading
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columns of other frames are indicated via `frame.Ci'
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The operations +, -, *, / and ** are supported with the same
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precedence as in FORTRAN. Parentheses may be used to change that
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order as well as to nest operations.
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The functions SQRT(a), EXP(a), EXP10(a), LN(a), LOG10(a), SIN(a)
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ASIN(a), COS(a), ACOS(a), TAN(a), ATAN(a), INT(a), ATAN2(a1,a2),
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MAX(a1,a2), MIN(a1,a2), MOD(a1,a2) and ABS(a), are implemented as in
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FORTRAN. Except that INT(a) will return the nearest integer of "a"
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The trigonometric functions expect arguments in degrees!
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Results of illegal operations (e.g. division by zero) are set to
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the "null value" defined by the keyword NULL.
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This command does not work with 1-dim frames!
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If columns from other frames are involved in the expression, they
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must have the same no. of pixels per column, i.e. NPIX(2).
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The no. of columns does not have to be the same.
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COMPUTE/ROW, COMPUTE/PLANE, COMPUTE/IMAGE, COMPUTE/XYPLANE
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COMPUTE/COLUMN tiburon.C22 = C100+C44
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Use image frame `tiburon.bdf' and add the 100th column to the
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44th column, store the result into the 22nd column of frame
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COMPUTE/COLUMN ballena.c7 = 99.9*sin(delfin.c125)
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Set the 7th column of frame `ballena.bdf' to the product of 99.9
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and the sine of the contents of column no. 125 of frame
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`delfin.bdf'. The no. of pixels per column of the two frames
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must be equal (i.e. same NPIX(2)).
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COMPUTE/COLUMN ballena.c2 = 2.*c27
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Compute 2.0 * 27th column of `ballena.bdf' and store result into
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second column of frame `ballena.bdf' .