# naginterfaces.library.stat.init_​vavilov¶

naginterfaces.library.stat.init_vavilov(rkappa, beta2, mode)[source]

init_vavilov is used to initialize functions pdf_vavilov() and prob_vavilov().

It is intended to be used before a call to pdf_vavilov() or prob_vavilov().

For full information please refer to the NAG Library document for g01zu

https://www.nag.com/numeric/nl/nagdoc_28.7/flhtml/g01/g01zuf.html

Parameters
rkappafloat

The argument of the function.

beta2float

The argument of the function.

modeint

If , pdf_vavilov() is to be called after the call to init_vavilov. Otherwise, prob_vavilov() is to be called.

Returns
xlfloat

, a threshold value below which will be set to zero by pdf_vavilov() and will be set to zero by prob_vavilov() if .

xufloat

, a threshold value above which will be set to zero by pdf_vavilov() and will be set to unity by prob_vavilov() if .

commdict, communication object

Communication structure.

Raises
NagValueError
(errno )

On entry, .

Constraint: .

(errno )

On entry, .

Constraint: .

(errno )

On entry, .

Constraint: .

(errno )

On entry, .

Constraint: .

(errno )

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 and/or and rerun init_vavilov.

Notes

init_vavilov initializes the array [‘rcomm’] for use by pdf_vavilov() or prob_vavilov() in the evaluation of the Vavilov functions and respectively.

Multiple calls to prob_vavilov() or pdf_vavilov() can be made following a single call to init_vavilov, provided that or do not change, and that either all calls are to prob_vavilov() or all calls are to pdf_vavilov(). If you wish to call both prob_vavilov() and pdf_vavilov(), then you will need to initialize both separately.

References

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