function L = neg_lik(rho,val,W,e)

%CON_LIK is the (negative) concentrated likelihood function
%
%INPUTS: (i)   rho = value of rho
%        (ii)  val = eigen values of W
%        (iii) W = weight matrix
%        (iv)  e = error vector
%        
%OUTPUT: L = value of concentrated likelihood 

n = length(W) ;

u = ones(length(val),1) ;

LogDet = u'*log(1 - rho*val) ; 

B = sparse(eye(n) - rho * W) ;

L =  (n/2) * log((1/n)*e'*B'*B*e) - LogDet;