Notes on Adding an Operator

To add a new operator to Chemist requires modifications in several places. They are collected here for convenience.

• Forward declare it in include/chemist/quantum_mechanics/operator/operator_fwd.hpp

• Declare the class in include/chemist/quantum_mechanics/operator/<operator_name>.hpp

• Define the class in src/chemist/quantum_mechanics/operator/<operator_name>.cpp

• Add it to the OperatorVisitor class in include/chemist/quantum_mechanics/operator/operator_visitor.hpp

• Define the new OperatorVisitor functions in src/chemist/quantum_mechanics/operator/operator_visitor.cpp

• Add unit tests to tests/cxx/unit_tests/quantum_mechanics/operator/<operator_name>.cpp

• Export it in src/chemist/quantum_mechanics/operator/operator/export_<operator_name>.cpp

• Add unit tests to tests/python/unit_tests/quantum_mechanics/operator/<operator_name>.py

Note

Operators templated on their particles are exported once per instantiation, under underscore-prefixed names, plus a single class Python actually uses that dispatches to them. Adding an instantiation therefore means adding it to that operator’s dispatch function as well; if you do not, the instantiation exists but nothing in Python can construct it. See export_dispatching_class in src/chemist/quantum_mechanics/operator/operator/py_operator_dispatch.hpp.

Note

“<operator_name>” in the above file names should be replaced with your operator’s actual name.

As a helpful hint, copy/paste kinetic.hpp / kinetic.cpp for one- particle operators and Coulomb.hpp / Coulomb.cpp for two-particle operators and then find/replace the name.