% @(#)computzypl.hlq 17.1.1.1 (ESO-IPG) 01/25/02 17:43:22 %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %.COPYRIGHT (c) 1990 European Southern Observatory %.IDENT computzypl.hlq %.AUTHOR KB, IPG/ESO %.KEYWORDS MIDAS, help files, COMPUTE/ZYPLANE %.PURPOSE On-line help file for the command: COMPUTE/ZYPLANE %.VERSION 1.0 12-OCT-1995 : Creation, KB %---------------------------------------------------------------- \se SECTION./ZYPL \es\co COMPUTE/ZYPLANE 12-OCT-1995 KB \oc\su COMPUTE/ZYPLANE result_cube = expression compute arithmetic expression on zy_planes of cubes \us\pu Purpose: Compute arithmetic expressions on the zy_planes of image cubes. \up\sub Subject: Arithmetic. \bus\sy Syntax: COMPUTE/ZYPLANE result_cube = expression \ys\pa result_cube = frame to get result of expression. The result frame will be created using real data format, no matter what data format the individual input frames have. \\ If descriptor copying is enabled (which is the default, see also the command SET/MIDAS_SYSTEM DSCCOPY=..), \\ all non-standard descriptors of the first 3-dim input frame in the expression are copied to the result frame unless you enter `frame,dscname' as result_cube with dscname the name of a frame in the expression; \\ then, the non-standard descriptors of that frame are copied instead of the ones of the first 3-dim frame in the expression \ap\pa expression = arithmetic expression with up to 21 operands, which may be functions and frames or/and constants in the usual algebraic notation \ap\no Note: The zy_plane of a cube is formed by the z- and y-axis and has NPIX(3) pixels per row and NPIX(2) pixels per column. \\ If a frame operand has NAXIS=2, the single plane of that frame is used in the computation for all zy_planes of the result frame. \\ If a frame operand has NAXIS=1, the single line of that frame is used in the computation for all lines of all zy_planes of the result frame. \\ There must be at least one 3-dim frame operand in the arithmetic expression, from which the dimensions of the result frame are taken over. \\ If the result frame has the same name as a frame appearing in the expression, no new frame is created, but the result frame is overwritten. Furthermore, since no new result frame is created, the final data is reconverted to the original data format when closing the result frame and you could get truncation errors! \\ 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), ABS(a), ATAN2(a1,a2), MAX(a1,a2), MIN(a1,a2) and MOD(a1,a2) \\ 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" stored in the real keyword NULL. \on\sa See also: COMPUTE/XYPLANE, COMPUTE/XZPLANE, COMPUTE/IMAGE \\ TRANSPOSE/CUBE, SET/MIDAS_SYS \as\exs Examples: \ex COMPUTE/ZYPLANE res3 = ima3+10*jma3 Compute the zy-planes of the resulting cube `res3.bdf' from the expression combining the zy-planes of the cubes `ima3.bdf' and `jma3.bdf'. The size and no. of zy-planes of the cubes `ima3.bdf' and `jma3.bdf' must be equal. \\ The dimensions of `res3.bdf' are taken from `ima3.bdf'. \\ If descriptor copying is enabled, also all non-standard descriptors of `ima3.bdf' (the 1. 3-dim frame in the expression) are copied to `res3.bdf'. \xe\ex COMPUTE/ZYPLANE res3,jma3 = ima3+10*jma3 As above, but if descriptor copying is enabled, all non-standard descriptors of `jma3.bdf' are copied to `res3.bdf'. \xe\ex COMPUTE/ZYPLANE res3 = ima2-ima3 Compute the zy-planes of the resulting cube `res3.bdf' from the difference of the 2-dim frame `ima2.bdf' and all zy-planes of the cube `ima3.bdf'. The size of `ima2.bdf' and the size of the zy-planes of `ima3.bdf' must be equal. That means, NPIX(1),(2) of `ima2.bdf' and NPIX(3),(2) of `ima3.bdf' must be equal. \\ The dimensions of `res3.bdf' are taken from `ima3.bdf'. \xe\ex COMPUTE/ZYPLANE res3 = ima2-ima3+sin(ima1) Compute the zy-planes of the resulting cube `res3.bdf' from the expression involving the 2-dim frame `ima2.bdf', the 3-dim frame `ima3.bdf' and the 1-dim frame `ima1.bdf'. The 2-dim frame `ima2.bdf' is used with all zy-planes of the cube `ima3.bdf'. Also, the 1-dim frame `ima1.bdf' is used with all lines of `ima2.bdf' and all lines of all zy-planes of `ima3.bdf'. The size of `ima2.bdf' and the size of the zy-planes of `ima3.bdf' must be equal. Also, the no. of pixels of `ima1.bdf' must be equal to the no. of pixels per line of the zy-planes of `ima3.bdf'. That means, NPIX(1) of `ima2.bdf' as well as of `ima1.bdf' must be equal to NPIX(3) of `ima3.bdf'. And NPIX(2) of `ima2.bdf' must be equal to NPIX(2) of `ima3.bdf'. \\ The dimensions of `res3.bdf' are taken from `ima3.bdf'. \xe \sxe