nag_prob_vavilov (g01euc) (PDF version)

g01 Chapter Contents

g01 Chapter Introduction

NAG Library Manual

NAG Library Function Document

nag_prob_vavilov (g01euc)

+− Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

+− 10 Example

10.1 Program Text

10.2 Program Data

10.3 Program Results

1 Purpose

nag_prob_vavilov (g01euc) returns the value of the Vavilov distribution function

Φ_{V} (λ; κ, β^{2})

.

It is intended to be used after a call to nag_init_vavilov (g01zuc).

2 Specification

#include <nag.h>

#include <nagg01.h>

double

nag_prob_vavilov (double x, const double comm_arr[])

3 Description

nag_prob_vavilov (g01euc) evaluates an approximation to the Vavilov distribution function

Φ_{V} (λ; κ, β^{2})

given by

Φ_{V} (λ; κ, β^{2}) = \int_{- \infty}^{λ} ϕ_{V} (λ; κ, β^{2}) d λ,

where

ϕ (λ)

is described in nag_prob_density_vavilov (g01muc). The method used is based on Fourier expansions. Further details can be found in Schorr (1974).

4 References

Schorr B (1974) Programs for the Landau and the Vavilov distributions and the corresponding random numbers Comp. Phys. Comm. 7 215–224

5 Arguments

1: x – doubleInput: On entry: the argument $λ$ of the function.
2: comm_arr[ $322$ ] – const doubleCommunication Array: On entry: this must be the same argument comm_arr as returned by a previous call to nag_init_vavilov (g01zuc).

6 Error Indicators and Warnings

None.

7 Accuracy

At least five significant digits are usually correct.

8 Parallelism and Performance

Not applicable.

9 Further Comments

nag_prob_vavilov (g01euc) can be called repeatedly with different values of

λ

provided that the values of

κ

and

β^{2}

remain unchanged between calls. Otherwise, nag_init_vavilov (g01zuc) must be called again. This is illustrated in Section 10.

10 Example

This example evaluates

Φ_{V} (λ; κ, β^{2})

at

λ = 0.1

,

κ = 2.5

and

β^{2} = 0.7

, and prints the results.

10.1 Program Text

Program Text (g01euce.c)

10.2 Program Data

Program Data (g01euce.d)

10.3 Program Results

Program Results (g01euce.r)

nag_prob_vavilov (g01euc) (PDF version)

g01 Chapter Contents

g01 Chapter Introduction

NAG Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2014