Hello Bill
I appreciate your help. I will try the energy method.
I'm wondering if can you download the Google Drive link for the "nodes1.dat", "element1.dat" and "nlist1.dat" for running the code.
Here is the link:
https://drive.google.com/drive/folders/1jy9AVwywknckaawVl_8z1B_ofg_1Lfk-?usp=sharing