NAG Library Routine Document
G01MTF returns the value of the Landau density function , via the routine name.
|REAL (KIND=nag_wp) G01MTF
G01MTF evaluates an approximation to the Landau density function
is an arbitrary real constant, using piecewise approximation by rational functions. Further details can be found in Kölbig and Schorr (1984)
To obtain the value of
can be used.
Kölbig K S and Schorr B (1984) A program package for the Landau distribution Comp. Phys. Comm. 31 97–111
- 1: X – REAL (KIND=nag_wp)Input
On entry: the argument of the function.
6 Error Indicators and Warnings
There are no failure exits from this routine.
At least significant digits are usually correct, but occasionally only . Such accuracy is normally considered to be adequate for applications in experimental physics.
Because of the asymptotic behaviour of , which is of the order of , underflow may occur on some machines when is moderately large and negative.
This example evaluates at , and prints the results.
9.1 Program Text
Program Text (g01mtfe.f90)
9.2 Program Data
Program Data (g01mtfe.d)
9.3 Program Results
Program Results (g01mtfe.r)