Parser warnings policy

As a rule of thumb, always include two keys in the output parameters of a calculation, warnings and parser_warnings. These two keys contain a list of messages (strings) that are useful for debugging problems in the execution of calculations. Below are the guidelines for the usage of the keys warnings and parser_warnings in the output parameters of a calculation.


These should be devoted to warnings or error messages relative to the execution of the code. As a (non-exhaustive) list of examples, for Quantum-ESPRESSO, run-time messages such as

  • Maximum CPU time exceeded.
  • c_bands:  2 eigenvalues not converged
  • Not enough space allocated for radial FFT
  • The scf cycle did not reach convergence.
  • The FFT is incommensurate: some symmetries may be lost.
  • Error in routine [...]

should be put in the warnings. In the above cases the warning messages are directly copied from the output of the code, but a warning can also be elaborated by the parser when it finds out that something strange went on during the execution of the code. For QE an example is QE pw run did not reach the end of the execution.

Among the code-based warnings, some can be identified as ‘’critical’‘, meaning that when present the calculation should be set in FAILED state. There should be an internal list in the parser, e.g. critical_messages, defining such critical warnings. Other non-critical warnings instead might be used to signal the presence of some possible source of troubles, but that nevertheless did not prevent the calculation to be considered FINISHED.


These should be reserved to warnings occurring during parsing, i.e. when the parser does not find an information it was looking for in the output files. For Quantum-ESPRESSO (PW), examples are

  • Skipping the parsing of the xml file.
  • Error while parsing for energy terms.
  • etc.

Therefore, these warnings should be placed just to notify that the output was not found in the way the developer had expected, and they signal the necessity of improving the parser code.