XANSONS for COD
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About XANSONS for COD

XANSONS for COD is a research project aimed to create an open access database of simulated x-ray and neutron powder diffraction patterns for nanocrystalline phase of the materials presented in the Crystallography Open Database (COD). You can participate by downloading and running a free program on your computer.

This project is in beta-testing stage. If no critical errors are found, all the results obtained during this stage will be included in the final database.

This project uses original open source (GPLv3 license) software XaNSoNS (X-ray and Neutron Scattering on Nanoscale Structures) to simulate the diffraction patterns on CPU and GPU.

XANSONS for COD is a privately managed BOINC project supported by the Russian Foundation for Basic Research (project RFBR #15-07-07901-a).

Scientific Problem

The conventional technique used to recover the structural properties of the crystalline samples by their powder diffraction pattern is the Rietveld refinement method. In this method, the theoretical powder diffraction pattern is refined until it fits the experimental one. The computation of the angles and intensities of the Bragg peaks can be made almost instantaneously in the approximation of the infinite size of the crystallite. To adjust for the finite size of the crystallites in the samples or finite resolution of the measurement device, these peaks are broadened artificially with the broadening function (usually Gaussian). This artificial broadening works great until the size of the crystallite in the sample is something below few tens of nanometers. For the such small crystallites, it is very hard to get the right broadening function which works fine for all Bragg peaks. Fortunately, for the such small crystallites, it is not a problem to calculate the powder diffraction patterns using the Debye equation (with the distance-histogram approximation, such as that proposed by Marcin Wojdyr and implemented in his Debyer code). This project is aimed to calculate the x-ray and neutron powder diffraction patterns for the nanocrystallites with the size varying from 6 nm to 30 nm for the most of the entries of the Crystallography Open Database. The two different types of materials are considered: (a) isolated spherical crystalline nanoparticle of a given size (diameter), (b) crystalline material with long-range order broken on the distances greater than a given value. The obtained database may simplify the diagnostics of the nanocrystalline samples and complement the Full Profile Search Match method in the crystallite size analysis of the nanocrystalline samples.

In addition to the above, the calculation of the powder diffraction pattern using the Debye equation allows to account the lattice defects such as site vacancies, atom replacements and displacements. So, if the Crystallography Information File (CIF) for the given structure provides the site occupancy numbers and atomic displacement parameters, the application will use them to calculate the diffraction pattern.

System Requirements

Supported operating systems: Supported GPUs:
  • Nvidia GPU with CUDA Compute Capability 1.3 and above (Windows, Linux) or 2.0 and above (OS X/macOS) with at least 1GB of memory (GDDR5 memory is recommended). Driver version 340.21 and above (Windows, Linux) or CUDA Driver for MAC version 7.0.29 and above (OS X/macOS).
  • AMD GPU with OpenCL 1.2+ support with at least 1GB of memory (integrated AMD GPUs, a.k.a. APUs, are not recomended, see Important Notes below).
  • Intel GPU of 8-th generation and above with OpenCL 1.2+ support (older Intel GPUs are not recommended, see Important Notes below).

Important Notes

  • The apps of this project do not make checkpoints. If stopped, the task will be restarted from the beginning. The task execution time should not exceed 10 minutes for moderate PCs. However, some tasks may take longer to complete on low-end PCs. This is particularly true for low-end GPUs. If the execution time of tasks is unacceptably high for your GPU, consider disabling it in the 'Preferences for this project' in your profile page.

  • Some antivirus software may place the executables into quarantine as unknown (and therefore suspicious) files. To prevent this from happening, disable blocking of unknown files in the antivirus preferences (e.g. in Avast disable CyberCapture feature). When BOINC client will download the executables, you can manually scan the BOINC data directory (C:\ProgramData\BOINC\ by default) for viruses. After that, the disabled antivirus functionality may be re-enabled again.

  • The algorithm which solves the problem on GPU uses 64-bit integer atomic functions on Nvidia and AMD GPUs and emulates them on Intel GPUs. All tested integrated AMD GPUs (APU) and all tested Intel GPUs below 8-th generation showed very poor performance for the tasks of this project probably caused by specific hardware architectures of these GPUs. If your GPU is affected, you can disable it in the 'Preferences for this project' in your profile page.

  • GPU apps do not require dedicated CPU core by default anymore. If you notice any performance issues caused by this, consider using custom app configuration. Place this file in the project’s folder.

  • The progress bar for GPU tasks may freeze on 0% for a few seconds. This is OK and does not mean that the app is hanging (at that time CPU computes the atomic ensemble and does not report a progress).

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I started to work for distributed computing in 2003, when I payed attention in the SETI@home project. In the same year I recognized the community of...

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Maintenance is over!
The project is restarted with new native BOINC apps and additional computational scenario.

Now the large WUs can be assigned only to the GPU and the small ones only to the CPU.

GPU apps do not require dedicated CPU core by default anymore. If you notice any performance issues caused by this, consider using custom app configuration. Place this file in the project's folder.

The apps of this project do not make checkpoints. If stopped, the task will be restarted from the beginning. The task execution time should not exceed 10 minutes for moderate PCs. However, some tasks may take longer to complete on low-end PCs. This is particularly true for low-end GPUs. If the execution time of tasks is unacceptably high for your GPU, consider disabling it in the "Preferences for this project" in your profile page.

The project is in beta-testing stage. Bugs are more than likely. However, all the results obtained during this stage will be included in the final database If no critical errors are found.

Thank you for participating! 18 Jun 2017, 18:09:05 UTC · Comment

Project restart in June
The maintenance is almost over. The new native BOINC apps are being tested in the local network now. We expect the project to be restarted at the end of next week. This will be preceded by server and storage upgrade. The work on the database is still in progress and will continue in parallel with the computations.

Also, the paper “XANSONS for COD: a new small BOINC project in crystallography” was accepted for presentation at the BOINC:FAST’2017 conference which is to be held in Petrozavodsk, Russia in August. 5 Jun 2017, 21:46:33 UTC · Comment

XaNSoNS is published in SoftwareX
The article about XaNSoNS, the software this project is based on, has been published in the peer-reviewed scientific journal SoftwareX. The article is open-access and can be found here.

The paper was submitted to the journal about a month before this project was launched, so I was able to add only a brief mention of the BOINC project during the revision process. 7 Feb 2017, 19:27:29 UTC · Comment

The number of project team members has doubled!
Nikolay Khrapov agreed to join the project in 2017 as a developer of the diffraction pattern database. He will also help with the system administration. Nikolay is known to the BOINC community primarily as the system administrator for the SAT@Home project. Now things will get easier!

Happy New Year! 31 Dec 2016, 14:49:01 UTC · Comment

Alpha-testing is over! The project is stopped for long-term maintenance.
The work generator is stopped. BOINC server will wait for all WUs that are in-progress. The site and the forum will continue to work during the maintenance. However, the registration of new users will be suspended. The TODO list can be found here.

The alpha-testing was successful! Here are some results and conclusions.


  • About 5.6% (~20,500 structures) of COD entries are processed. The collected data will be used to determine the optimal set of crystallite sizes and the optimal resolution of the simulated diffraction patterns for the final database.
  • A few critical bugs (see e.g., 1, 2 and 3) in the app are fixed thanks to volunteers who participated in debugging on this site and on http://boinc.ru. All apps are sufficiently stable now. A fraction of fails is about 1% (see, e.g., these statistics for November 27th).
  • The site functionality was improved thanks to the advices given by volunteers.
  • The optimal parameters of the virtual server are determined: 2 cores of Intel Xeon E5-2666, 4 GB RAM, 500 GB SSD storage with read/wright throughput of 1500 IOPS, network load: 60 MB/s.
  • The processing power donated by volunteers to this project was much higher than expected. This allows to extend the initial range of crystallite sizes to larger sizes (up to 30 nm).
  • Although the MultiSize feature has slightly improved the scheduling, it is still far from optimal. It is clear now that CPU and GPU apps should receive WUs of different size due to large difference in performance. It is also clear that single-threaded CPU app is required to process small WUs. So, the distribution of WUs for different crystallite sizes between the apps should be like this:

    CPU, single-threaded: < 10 nm
    CPU, multi-threaded: 10 – 20 nm
    GPU: > 20 nm

I will post the progress of work from time to time. However, please do not expect much until the spring of 2017.

I am very grateful to all volunteers participating in the alpha-testing! I apologize for poor server performance, awful job scheduling, app crashes and bugs leading to a waste of computational resources. Thank you for your patience and understanding! 29 Nov 2016, 17:00:36 UTC · Comment

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