% SR_LAGUERRELOG1  This computes the first N recurrence 
%    coefficients alpha_k, beta_k, k=0,1,\ldots,N-1, to an 
%    accuracy of nofdig digits for the system of polynomials 
%    orthogonal with respect to the weight function 
%                 w(x)=x^a e^{-x}(x-1-log x), 
%    using modified moments relative to the monic generalized 
%    Laguerre polynomials. The output variable ab is the Nx2 
%    array of the nofdig-digit recurrence coefficients, and 
%    dig is the number of digits required to achieve the 
%    target precision of nofdig decimal places using successive
%    calculations with precisions incremented in steps of dd
%    digits. The number dd in the first statement of the routine,
%    as well as dig0, can be changed by the user as seen 
%    appropriate. 
%
function [ab,dig]=sr_laguerrelog1(N,a,nofdig)
syms mom ab ab0 ab1 abn 
dd=10; dig0=nofdig;
ii=dig0-dd; 
maxerr=1;
while maxerr>.5*10^(-nofdig)
  ii=ii+dd; dig=ii
  mom=mmomlaglog(dig,N,a);
  abm=sr_laguerre(dig,2*N-1,a);
  if ii==dig0
    ab0=schebyshev(dig,N,mom,abm);
  else
    ab1=schebyshev(dig,N,mom,abm);
    serr=vpa(abs((ab1-ab0)./ab1),dig);
    err=subs(serr);
    maxerr=max(max(err)); 
    ab0=ab1;
   end
end
ab=vpa(ab1,nofdig);