1: $x$ – Real (Kind=nag_wp) Input: On entry: the argument $λ$ of the function.
2: $rcomm (322)$ – Real (Kind=nag_wp) array Communication Array: On entry: this must be the same argument rcomm as returned by a previous call to g01zuf.
3: $ifail$ – Integer Input/Output: On entry: ifail must be set to $0$ , $−1$ or $1$ to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of $0$ causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of $−1$ means that an error message is printed while a value of $1$ means that it is not.

If halting is not appropriate, the value $−1$ or $1$ is recommended. If message printing is undesirable, then the value $1$ is recommended. Otherwise, the value $0$ is recommended. When the value $- 1$ or $1$ is used it is essential to test the value of ifail on exit.

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

6 Error Indicators and Warnings

If on entry

ifail = 0

−1

, explanatory error messages are output on the current error message unit (as defined by x04aaf).

Errors or warnings detected by the routine:

$ifail = 1$: Either the initialization routine has not been called prior to the first call of this routine or a communication array has become corrupted.

$ifail = - 99$: An unexpected error has been triggered by this routine. Please contact NAG.
See Section 7 in the Introduction to the NAG Library FL Interface for further information.

$ifail = - 399$: Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library FL Interface for further information.

$ifail = - 999$: Dynamic memory allocation failed.
See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

At least five significant digits are usually correct.

g01muf is not threaded in any implementation.

g01muf can be called repeatedly with different values of

λ

provided that the values of

κ

and

β^{2}

remain unchanged between calls. Otherwise, g01zuf must be called again. This is illustrated in Section 10.

This example evaluates

ϕ_{V} (λ; κ, β^{2})

λ = 2.5

κ = 0.4

and

β^{2} = 0.1

, and prints the results.

g01mu: FL CL CPP AD