 Usage:  {A,V,ctrl}=itera(A0,FI,b,N,eps,itmax,expl)  
 
 Input:

  A0                     p x p; starting value for A; if 0 is entered I^{-1} is taken 
                         if p>1 and dim(A0)==1 I^{-1}*A0 is taken 
                         
  FI                     p x p; Fisher-Information 
                         
  b                      numeric; clipping height 
                         
  N                      integer; MC-sample size / integration grid-points 
                         
  eps                    numeric; exactitude 
                         
  itmax                  integer; maximal number of iterations 
                         
  expl                   numeric; threshold for the changes in abs. value of A: 
                         beyond this value convergence is uncertain ~ 4 
                         
 Output:

  A                      p x p; Lagrange-Multiplyer solving (1) 
                         
  V                      p x p; corresponding Covariance 
                         
  ctrl                   integer; tells if convergence "happened" 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
