Towards a Common Format for Computational Material Science Data

TL;DR

This paper discusses the development of a standardized, code-independent data format for computational materials science, emphasizing the complementary strategies of converters and open libraries to facilitate data exchange.

Contribution

It introduces a unified format and conventions for electronic-structure data, developed collaboratively by ESL and NOMAD, promoting standardization in the field.

Findings

Agreed upon a common data format and conventions.

Demonstrated the complementarity of converters and open libraries.

Defined hierarchical metadata for electronic-structure calculations.

Abstract

Information and data exchange is an important aspect of scientific progress. In computational materials science, a prerequisite for smooth data exchange is standardization, which means using agreed conventions for, e.g., units, zero base lines, and file formats. There are two main strategies to achieve this goal. One accepts the heterogeneous nature of the community which comprises scientists from physics, chemistry, bio-physics, and materials science, by complying with the diverse ecosystem of computer codes and thus develops "converters" for the input and output files of all important codes. These converters then translate the data of all important codes into a standardized, code-independent format. The other strategy is to provide standardized open libraries that code developers can adopt for shaping their inputs, outputs, and restart files, directly into the same code-independent format. We like to emphasize in this paper that these two strategies can and should be regarded as complementary, if not even synergetic. The main concepts and software developments of both strategies are very much identical, and, obviously, both approaches should give the same final result. In this paper, we present the appropriate format and conventions that were agreed upon by two teams, the Electronic Structure Library (ESL) of CECAM and the NOMAD (NOvel MAterials Discovery) Laboratory, a European Centre of Excellence (CoE). This discussion includes also the definition of hierarchical metadata describing state-of-the-art electronic-structure calculations.