function [n_cand,Cand_models]=pru_step(Model,InpPat);

n_cand=0;

disp(['Purging Step']);
n_s_b=Model.n_s_m;

%Decrease order of univariate sub_models
[n_c,C_m]=dec_ord_sm(Model,InpPat);
if n_c>0
   Cand_models(n_cand+1:n_cand+n_c)=C_m;
   n_cand=n_cand+n_c;
   disp([num2str(n_c) ' univariate submodels with spline order decreased']);
end  

% splitting multivariate submodels
[n_c,C_m]=spl_mv(Model,InpPat);
if n_c>0
   Cand_models(n_cand+1:n_cand+n_c)=C_m;
   n_cand=n_cand+n_c;
   disp([num2str(n_c) ' multivariate submodels splitted']);
end 
   
% removing knots 
[n_c,C_m]=rem_kv(Model,InpPat);
if n_c>0
   Cand_models(n_cand+1:n_cand+n_c)=C_m;
   n_cand=n_cand+n_c;
   disp([num2str(n_c) ' submodels with knots removed']);
end 

if n_cand==0
   Cand_models=[];
end