- Type: System..::..DoubleOn entry: the argument of the function.
g01rt evaluates an approximation to the derivative of the Landau density function given by
where is described in g01mt, using piecewise approximation by rational functions. Further details can be found in Kölbig and Schorr (1984).
To obtain the value of , g01mt can be used.
Kölbig K S and Schorr B (1984) A program package for the Landau distribution Comp. Phys. Comm. 31 97–111
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.