Derived Field New API

[cindytsai]

Derived Field New API

Add new data member derived_func_with_name to yt_field struct.

• Data type:void (*derived_func_with_name) (long gid, char *field, double *data)
• Usage: get the universal derived function pointer.
• Description:
  • If field_define_type == "derived_func", then one should set either derived_func or derived_func_with_name for its data generating function.
  • This new added data member is capable of generating desired data through gid and field name.
  • The searching order for derived function is (1) derived_func (2) derived_func_with_name.

Update Example

• Demonstrate how to use derived field, which is generating field data only when needed in libyt.

Update GitHub Action

• Update workflow to also test derived field.