|Routine ID: G116|
|Author(s): B. Schorr, K.S. Kölbig||Library: MATHLIB|
|Submitter: K.S. Kölbig||Submitted: 10.12.1993|
The VVILOV package contains subprograms for the calculation of the Vavilov density and distribution functions. Though generally more accurate, these routines are considerably slower than those in VAVLOV (G115).
For and , the Vavilov density function is mathematically defined by
where c is an arbitrary real constant and
is the exponential integral, , and is Euler's constant.
The Vavilov distribution function is defined by
SUBROUTINE and FUNCTION subprograms
User Entry Names: VVISET, VVIDEN, VVIDIS
Internal Entry Names: G116F1, G116F2
External References: RZERO (C205), RSININ, RCOSIN (C336), REXPIN (C337)
COMMON Block Names and Lenghts: /G116C1/ 322
CALL VVISET(RKAPPA,BETA2,MODE,XL,XU)sets auxiliary quantities used in VVIDEN and VVIDIS; this call has to precede a reference to either of these entries.
RKAPPA, BETA2, XL and XU are defined by the last call to VVISET (with ) prior to a reference to VVIDEN, or (with ) prior to a reference to VVIDIS.
VVIDEN, VVIDIS and X, RKAPPA, BETA2, XL, XU are of type REAL, and MODE is of type INTEGER.
The method, based on Fourier expansions, is described in Ref. 1.
About five significant digits are usually accurate.
Error G116.2: .
These errors can occur when calling VVISET. In both cases, a message is written on Unit 6, unless subroutine MTLSET (N002) has been called.