function [P]=AsympLegendreP(l,theta);
% MATLAB HELP:
% 
% function [P]=AsympLegendreP(l,theta);
%
% approximate legendre polynomial of degree evaluated at cos(theta) 
%
% inputs:
%  l, angular degree
%  theta, the angle, this can be a vector of angles
% outputs:
%   P, approximate legendre polynomial
%
%
% see codes.ps or codes.pdf for details
%
% aaron birch, may 21, 2002


if (l<100)
	g=gamma(l+1)/gamma(l+3/2);
else
	g=1/sqrt(l);
end;

k=g*sqrt(2/pi);


P=k * cos( (l+1/2)*theta-pi/4)./sqrt(sin(theta));