mlamv.f90

数值计算和数值分析在Fortran下的特殊函数库,是数值计算的必备

MODULE lamv_func
 
! From the book "Computation of Special Functions"
!      by Shanjie Zhang and Jianming Jin
!   Copyright 1996 by John Wiley & Sons, Inc.
! The authors state:
!   "However, we give permission to the reader who purchases this book
!    to incorporate any of these programs into his or her programs
!    provided that the copyright is acknowledged."

! Latest revision - 5 February 2002
! Corrections by Alan Miller (amiller @ bigpond.net.au)
! (25) in routine GAM0 changed to g(25)
 
IMPLICIT NONE
INTEGER, PARAMETER  :: dp = SELECTED_REAL_KIND(12, 60)
 
CONTAINS
 

SUBROUTINE lamv(v, x, vm, vl, dl)

!    =========================================================
!    Purpose: Compute lambda function with arbitrary order v,
!             and their derivative
!    Input :  x --- Argument of lambda function
!             v --- Order of lambda function
!    Output:  VL(n) --- Lambda function of order n+v0
!             DL(n) --- Derivative of lambda function
!             VM --- Highest order computed
!    Routines called:
!         (1) MSTA1 and MSTA2 for computing the starting
!             point for backward recurrence
!         (2) GAM0 for computing gamma function (|x|