YAML

Most configuration settings for the IESopt optimization model are stored in YAML files. This section provides a reference for the YAML syntax and the specific settings used in IESopt.

Yet another markup language?

YAML - which actually stands for YAML Ain’t Markup Language - is a human-readable data serialization language. It is often used for configuration files and data exchange between languages. YAML is a superset of JSON, meaning that any valid JSON file is also a valid YAML file.

You can find more information at:

Good to know

The following points offer hints, notes, or recommendations for working with YAML files in IESopt:

  • Indentation: YAML files make use of indentation: The recommended indentation is two spaces.

  • Comments: Comments in YAML files are preceded by a # character.

  • Dictionaries: YAML files are often used to define dictionaries. In Python (and Julia), dictionaries are/were unordered[1], and the order of (dictionary) entries are therefore not considered to have any specific order. However, the order given in the documentation is recommended for readability.

Danger

Since we are using dictionaries to store most configurations inside the YAML files, be aware that keys have to be unique. No key can exist twice in the same dictionary - this means, e.g., that you cannot use two components with the same name. However, depending on the implementation of the YAML parser, duplicate keys might not raise an error: After loading a YAML file IESopt will only be able to see the last value of a duplicate key, without any way to detect that ambiguity.

This is a common source of errors, so be careful!

Contents

See the documentation of the built-in YAML here: