function logprior = lipoprior_abs(pars,path,prior_pars)

% our prior has zero density when the expectation surface is outside of our bounds

pars(2)=abs(pars(2));
if  prod(prod(+(path>=prior_pars(1,1)&path<=prior_pars(1,2))))~=1 
    logprior=-inf;
else
    % the priors for the initial states are gammas and the prior for the
    % error term is an inverse gamma
logprior =  log(gampdf(1/pars(3),prior_pars(2,1),prior_pars(2,2)));
end


