function ab=sr_meixner_pollaczek(dig,N,lambda,phi)
%SR_MEIXNER_POLLACZEK Recurrence coefficients for 
%Meixner-Pollaczek polynomials.
%   AB=SR_MEIXNER_POLLACZEK(DIG,N,LAMBDA,PHI) generates in
%   DIG-digit arithmetic the Nx2 array AB of the first N 
%   recurrence coefficients for polynomials orthogonal on
%   [-Inf,Inf] relative to the weight function 
%   w(x)=(2*pi)^(-1)*exp((2*PHI-pi)*x)*|gamma(LAMBDA+i*x)|^2, 
%   LAMBDA>0, 0<PHI<pi. The call AB=SR_MEIXNER_POLLACZEK
%   (DIG,N,LAMBDA) is the same as AB=SR_MEIXNER_POLLACZEK
%   (DIG,N,LAMBDA,pi/2).

digits(dig);
if nargin<4, phi=pi/2; end
if ((N<=0)|(lambda<=0)|(phi<=0)|(phi>=pi)) 
  error('parameter(s) out of range') 
end
phi=vpa(phi); lambda=vpa(lambda); s2=vpa(2); s4=vpa(4);
n=(1:N)'; sinphi=sin(phi); lam2=s2*lambda;
if double(sinphi)==1
  ab(:,1)=vpa(zeros(N,1));
else
  ab(:,1)=-(vpa(n-1)+lambda)/tan(phi);
end
ab(:,2)=vpa((n-1)).*(vpa(n-2)+lam2)/(s4*sinphi^2);
ab(1,2)=gamma(lam2)/((s2*sinphi)^lam2);
