Takin: An open-source software for experiment planning, visualisation, and data analysis

TL;DR

Takin is an open-source software tool designed to assist researchers in planning, visualizing, and analyzing data for neutron triple-axis spectrometer experiments, improving accuracy and efficiency.

Contribution

It introduces a configurable, free software system that streamlines experiment planning, execution, and data analysis for neutron triple-axis spectrometers.

Findings

Successfully tested at MLZ

Configurable for different instruments

Enhances experiment accuracy and efficiency

Abstract

Due to the instrument's non-trivial resolution function, measurements on triple-axis spectrometers require extra care from the experimenter in order to obtain optimal results and to avoid unwanted spurious artefacts. We present a free and open-source software system that aims to ease many of the tasks encountered during the planning phase, in the execution and in data treatment of experiments performed on neutron triple-axis spectrometers. The software is currently in use and has been successfully tested at the MLZ, but can be configured to work with other triple-axis instruments and instrument control systems.

Tables

Table 1. Table 1 : Code metadata

Nr.	Code metadata description
C1	Current code version	1.5
C2	Permanent link to code/repository used for this code version	https://github.com/t-weber/takin
C3	Legal Code License	GNU GPL Version 2
C4	Code versioning system used	git
C5	Software code languages, tools, and services used	C++ 11, CMake 3
C6	Compilation requirements, operating environments	Linux, OS X, Unix like, Windows (via MinGW); GCC 4.8 (or later) or Clang, Boost, Qt 4 or 5, Qwt 5 or 6, Clipper, Minuit 2, Freetype
C7	If available Link to developer documentation/manual	https://forge.frm2.tum.de/cgit/cgit.cgi/frm2/mira/tastools.git/plain/doc/index_help.html
C8	Support email for questions	tobias.weber@tum.de

Table 2. Table 2 : Executable metadata

Nr.	(executable) Software metadata description
S1	Current software version	1.5
S2	Permanent link to executables of this version	http://wiki.mlz-garching.de/takin
S3	Legal Code License	GNU GPL Version 2
S4	Computing platform / Operating System	Linux, OS X, Unix like, Windows (MinGW test version)
S5	Installation requirements & dependencies
S6	If available Link to user manual	http://wiki.mlz-garching.de/takin
S7	Support email for questions

Full text

This was the 2017 pre-print of our software paper [1], which is now available at http://dx.doi.org/10.1016/j.softx.2017.06.002 and is licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). As pre-print, it is a modified form of the published paper. Furthermore, small updates have been included in the present version, e.g. concerning the references.

††journal: SoftwareX

1 Introduction

Several updates to the free and open-source software (FOSS) Takin [2, 3] have been made over the course of the last year. Apart from general performance optimisations and improvements of the existing programme modules, new features have been introduced. Of these features, we present two selected ones in the present short paper.

2 3D Brillouin zones

The previous version of our software included code to calculate a two-dimensional (2D) slice of the first Brillouin zone relevant for the selected scattering plane. For complexity and performance reasons, the code used for the task remained purely 2D. While this gives reasonable results in most cases, it is only an approximation.

For the present version, we created a new programme module which calculates the full three-dimensional (3D) Brillouin zone from the single-crystal parameters and the space group on-the-fly. The code is highly optimised and has only a very slight performance penalty when compared to the old 2D version. The Brillouin zone can now either be visualised in the software using OpenGL [4] or be exported to the open X3D file format. The X3D export allows for processing the data in external applications, for instance the FOSS programme Blender [5]. Furthermore, 2D cuts of the 3D Brillouin zones are generated using the selected scattering plane. These cuts are presented in the main reciprocal space display, replacing the old pure-2D code. An example for these calculations is shown in Fig. 1.

3 Scripting interfaces

In its resolution convolution code, Takin uses externally supplied scripts for the calculation of the dynamical structure factor $S\left(\mathbf{Q},E\right)$. In addition to Python [6], we now support the novel scripting language Julia [7] for this task. As Julia is just-in-time compiled, it considerably speeds up the calculation of the convolution integral.

In order to circumvent threading limitations in the Python interpreter and for stability reasons, both the Python and Julia scripting interfaces are now separated from the main programme. $S\left(\mathbf{Q},E\right)$ script modules are now spawned in their own process space and communicate with Takin using a shared-memory messaging system.

Acknowledgements

This work was supported by the German Research Foundation (DFG) and the Technische Universität München within the funding programme Open Access Publishing. We are mainly indebted to Peter Böni and Robert Georgii for their continuing support of these scientific computing projects. Additionally, we want to thank Petr Čermák, Astrid Schneidewind, Jitae Park, Greg Tucker, and Bertrand Roessli for helpful discussions and for reporting bugs in the previous version of the software. Many thanks go to Alain Filhol for his continuous help on improving the OS X build. Also thanks to Petr Čermák for his website at MLZ, which hosts the binaries.

The software’s DOI is: 10.5281/zenodo.3961491.

Required Metadata

Current code version UPDATE

Current executable software version