function [p,z] = pz(algor)
%
%  This function computes the poles and zeros for different integration algorithms
%
z = tf('z',1);
%
%  1 = Backinterpolation 4th/5th order based on RKF 4/5 with theta =  0.45
%
if algor==1,
  theta = 0.45;
  zf = z*theta;
  zf2 = zf*zf;
  zf3 = zf2*zf;
  zf4 = zf3*zf;
  zf5 = zf4*zf;
  Gf = 1 + zf + zf2/2 + zf3/6 + zf4/24 + zf5/104;
  zb = z*(1 - theta);
  zb2 = zb*zb;
  zb3 = zb2*zb;
  zb4 = zb3*zb;
  zb5 = zb4*zb;
  zb6 = zb5*zb;
  Gb = 1 - zb + zb2/2 - zb3/6 + zb4/24 - zb5/120 + zb6/2080;
  G = Gb\Gf;
  G = zpk(G);
  [z,p,k] = zpkdata(G,'v');
  return,
end
%
return
