NAG Library Routine Document

g01zuf  (init_vavilov)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{rkappa}$ – Real (Kind=nag_wp)Input

On entry: the argument $\kappa$ of the function.

Constraint: $0.01\le \mathbf{rkappa}\le 10.0$.

2:     $\mathbf{beta2}$ – Real (Kind=nag_wp)Input

On entry: the argument ${\beta }^2$ of the function.

Constraint: $0.0\le \mathbf{beta2}\le 1.0$.

3:     $\mathbf{mode}$ – IntegerInput

On entry: if $\mathbf{mode}=0$, g01muf is to be called after the call to g01zuf. Otherwise, g01euf is to be called.

4:     $\mathbf{xl}$ – Real (Kind=nag_wp)Output

On exit: $x_l$, a threshold value below which ${\varphi }_V\left(\lambda \text{;}\kappa ,{\beta }^2\right)$ will be set to zero by g01muf and ${\Phi }_V\left(\lambda \text{;}\kappa ,{\beta }^2\right)$ will be set to zero by g01euf if $\lambda <x_l$.

5:     $\mathbf{xu}$ – Real (Kind=nag_wp)Output

On exit: $x_u$, a threshold value above which ${\varphi }_V\left(\lambda \text{;}\kappa ,{\beta }^2\right)$ will be set to zero by g01muf and ${\Phi }_V\left(\lambda \text{;}\kappa ,{\beta }^2\right)$ will be set to unity by g01euf if $\lambda >x_u$.

6:     $\mathbf{rcomm}\left(322\right)$ – Real (Kind=nag_wp) arrayCommunication Array

On exit: this argument should be passed unchanged to g01euf or g01muf.

7:     $\mathbf{ifail}$ – IntegerInput/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this argument, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6

Error Indicators and Warnings

$\mathbf{ifail}=1$

On entry, $\mathbf{beta2}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{beta2}\ge 0.0$.

On entry, $\mathbf{beta2}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{beta2}\le 1.0$.

On entry, $\mathbf{rkappa}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{rkappa}\ge 0.01$.

On entry, $\mathbf{rkappa}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{rkappa}\le 10.0$.

$\mathbf{ifail}=2$

The initialization has been abandoned due to an internal error. This error exit is unlikely to occur, but if it does change the values of rkappa and/or beta2 and rerun g01zuf.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 3.9 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 3.8 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example