At present，I‘m going to deal with the basis function using a spacial algorithm to realize optimizing finite element method， so I’m facing the following two challenges：
（1）With knowing mesh “TH” ，I can use the code " fespace Vh(TH,p1);" to get the finite element space. How can I get the basis functions of the space “Vh”?
(2) If I have had some basis functions “a1, a2, …, an” on the mash “TH”, how can I build a new finite element space?
Thank you advance!