public static double g01rt(
	double x
)

Public Shared Function g01rt ( _
	x As Double _
) As Double

public:
static double g01rt(
	double x
)

static member g01rt : 
        x : float -> float 

g01rt returns the value of the derivative ${\varphi }^{\prime }\left(\lambda \right)$ of the Landau density function.

g01rt evaluates an approximation to the derivative ${\varphi }^{\prime }\left(\lambda \right)$ of the Landau density function given by where $\varphi \left(\lambda \right)$ 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 $\varphi \left(\lambda \right)$, 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 $7$ significant digits are usually correct, but occasionally only $6$. Such accuracy is normally considered to be adequate for applications in experimental physics.

Because of the asymptotic behaviour of ${\varphi }^{\prime }\left(\lambda \right)$, which is of the order of $\exp \left[-\exp \left(-\lambda \right)\right]$, underflow may occur on some machines when $\lambda$ is moderately large and negative.

None.

None.

This example evaluates ${\varphi }^{\prime }\left(\lambda \right)$ at $\lambda =0.5$, and prints the results.