anchor.diff:  C
   C       ======================================================
   C       Purpose: Compute the integrals of Airy fnctions with
  -C                respect to t from 0 and x ( x  0 )
  +C                respect to t from 0 and x ( x ≥ 0 )
   C       Input  : x   --- Upper limit of the integral
   C       Output : APT --- Integration of Ai(t) from 0 and x
   C                BPT --- Integration of Bi(t) from 0 and x
  
positive.code: C       Input :  M  --- Maximum order of Mathieu functions
  C                q  --- Parameter of Mathieu functions
  C                KD --- Case code
  C                       KD=1 for cem(x,q)  ( m = 0,2,4, )
  C                       KD=2 for cem(x,q)  ( m = 1,3,5, )
  C                       KD=3 for sem(x,q)  ( m = 1,3,5, )
  C                       KD=4 for sem(x,q)  ( m = 2,4,6, )
  C       Output:  CV(I) --- Characteristic values; I = 1,2,3,...
  C                For KD=1, CV(1), CV(2), CV(3),..., correspond to
  C                the characteristic values of cem for m = 0,2,4,...
  
negative.code: C       Output:  VV(na) --- Vv(x)
  C                VP(na) --- Vv'(x)
  C                ( na = |n|, v = n+v0, |v0| < 1
  C                  n = 0,±1,±2,… )
  C                PVF --- Vv(x)
  C                PVD --- Vv'(x)
  C       Routines called:
  