%This function computes the Palm distribution
% of the angle of the normal to the level curve 
% Entries are 
% gamma=  smaller  /  larger eigen values   of Var(W') 
% kapa = angle  of the direction  of lambda+ (greater eigenvalue of Var(W')
 % Jean-Marc Azaïs  is the author of this script 
%Tlse 3 2009
function z=anisotrop2(gamma, kapa) 

phi = pi/2*( -1:0.01:1);
n=(1- gamma^2* (sin(phi-kapa)).^2).^(-0.5);
 [K,E] =Ellipke(gamma^2) ; % seul K sert
 d = 4*K
%
z=n/d;
plot(phi,z) ;
sum(z)* 0.01* pi/2