Hessian PDF Covariance Matrix for theory predictions
Created by: comane
The idea of this PR is to have the covmats.pdferr_plus_covmat
function to take into account for the case in which the PDF has error_type = 'symmhessian'
Created by: comane
The idea of this PR is to have the covmats.pdferr_plus_covmat
function to take into account for the case in which the PDF has error_type = 'symmhessian'