XMM-Newton Science Analysis System


selectlib (selectlib-4.78.1) [22.0.0-9173c7d25-20250127]

Arithmetic constants and identifiers

Boolean and arithmetic expressions may contain integer and floating point constants which can be specified as in C/C++ or Fortran, e.g. 1.234E-12, -23, .111222, 1e2. The value of an integer constant can be given in binary, octal, or hexadecimal by prepending b, o, and h or 0x respectively, i.e., $32482 = \mbox{b111111011100010} = \mbox{o77342} = \mbox{0x7ee2} = \mbox{h7ee2}$. Some frequently used constants are available as symbolic names:

name	type	value	comment
#PI	real	$\pi = 3.1415926535\ldots$
#E	real	$e = 2.718281828\ldots$	Euler number
#RAD	real	$\pi/180 = 0.017453\ldots$	for deg $\longrightarrow$ rad conversion
#DEG	real	$180/\pi = 57.29577\ldots$	for rad $\longrightarrow$ deg conversion
#ARCSEC	real	$\pi/180/3600 = 4.8481\ldots^{-6}$	1 arcsec expressed in rad
#ARCMIN	real	$\pi/180/60 = 2.9088\ldots^{-4}$	1 arcmin expressed in rad
TRUE	boolean	true
FALSE	boolean	false