ASINH
Name
ASINH
Purpose
Return the inverse hyperbolic sine of the argument
Explanation
The inverse hyperbolic sine is used for the calculation of asinh
magnitudes, see Lupton et al. (1999, AJ, 118, 1406)
Calling Sequence
result = asinh( x)
Inputs
X - hyperbolic sine, numeric scalar or vector or multidimensional array
(not complex)
Output
result - inverse hyperbolic sine, same number of elements as X
double precision if X is double, otherwise floating pt.
Method
Expression given in Numerical Recipes, Press et al. (1992), eq. 5.6.7
Note that asinh(-x) = -asinh(x) and that asinh(0) = 0. and that
if y = asinh(x) then x = sinh(y).
Revision History
Written W. Landsman February, 2001
Work for multi-dimensional arrays W. Landsman August 2002
Simplify coding, and work for scalars again W. Landsman October 2003