%XGO200 The value of x which, for given n, requires
%   more than 200 Gauss points to achieve an accuracy
%   eps0  
% 
function x=xgo200(n)
global ab ab0
N0=195; dN=1;
eps0=.5e-12; tol=.5e-5;
for x=-1:-1:-30
  [N,y,go200]=N_inerfc(n,x,eps0,N0,dN);
  if go200==1
    a=x; b=x+1;
    break
  end
end
%[a b]
%[N,y,go200]=N_inerfc(n,a,eps0,N0,dN); go200
%[N,y,go200]=N_inerfc(n,b,eps0,N0,dN); go200
ktol=ceil(log((b-a)/tol)/log(2));
for k=1:ktol
%  [a b]
%  [N,y,go200]=N_inerfc(n,a,eps0,N0,dN); go200
%  [N,y,go200]=N_inerfc(n,b,eps0,N0,dN); go200
  x=(a+b)/2;
  [N,y,go200]=N_inerfc(n,x,eps0,N0,dN);
  if go200==0, b=x; else a=x; end
end
