The Computational Materials Repository

86 Appendix4.4 Inside a db-fileA minimal db-file is a compressed tar.bz2 container containing a file named”info.xml”. ”info.xml” contains the data of either a calculation or the definitionfor a group of calculations. Figure 4.1 shows an example of XML code todemonstrate how the data is stored in ”info.xml”:. . .−586.44247716268. . .. . .Figure 4.1: XML extract from a GPAW calculation as it is stored within ”info.xml”in a db-file. The content is as follows: T otalEnergy = −586.442477162 andAtomicNumbers = [6, 8]. ”double”, ”long array” and ”long” are the names of theinternal type.The XML-file is divided into seven paragraphs as illustrated in 4.4:• static: data that is present in every db-file like the date and the user name• extras: information that describe the calculation like keywords and adescription• calculator: all data from the original calculator output that was selectedto go into the db-file• user: custom data that the user can chosen freely• ASE: data from retrieved from the ASE interface; only available, if ASEis used with this file format; this will contain some duplicate data that isalready present in the calculator paragraph - but the units will be eV andthe coordinate absolute and not relative.• history: when db-files are modified and the hash value changes theprevious hash value should be kept as a backup; in the future there mightbe ability to search also for older hash values• runtime: information about how the calculation was run. Currently noneof the converter collects this information automatically