Some confuse about commands

Need help here from a new user:
1:what is the difference between “CreateSolution” 、 “Node_Solution"、” Edge_Solution” and
"Element_Solution” when creating models?
2:What is the differnece between “node_solution()” and “node_model” when creating an node model ?

CreateSolution is a helper function in one of the python_packages module scripts.

node_solution is a type of node_model, but without an equation behind it. You can use a node solution to store data. The set_node_values command can store data.

The pattern is similar for the edge and element models. An edge model is for each edge in a region. An element model is for each triangle edge in 2d, and for each element edge in 3d. I try to describe this formalism here: