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| 1 | +This test is a whole-program test of the SNMF Optimizer. It runs the optimization on known data with fixed, trusted settings, then asserts |
| 2 | +whether the objective function is below a certain value after exactly a certain number of iterations. |
| 3 | +It is a blunt-force instrument that can tell if a PR has completely broken things, but it will not catch regressions, and its method |
| 4 | +of using objective function only can inadverdently validate a degenerate result. Use with caution. |
| 5 | + |
| 6 | +This test uses data published in: |
| 7 | +Stretched Non-negative Matrix Factorization[J]. |
| 8 | +Section 5.4 XRD |
| 9 | +Tab. 7, Fig. 8 & 9 |
| 10 | +Gu R, Rakita Y, Lan L, et al. |
| 11 | +Stretched Non-negative Matrix Factorization[J]. |
| 12 | +arXiv preprint arXiv:2311.15173, 2023. |
| 13 | +and later republished as: |
| 14 | +Gu, R., Rakita, Y., Lan, L. et al. Stretched non-negative matrix factorization. |
| 15 | +npj Comput Mater 10, 193 (2024). https://doi.org/10.1038/s41524-024-01377-5 |
| 16 | +Data description: |
| 17 | +"A stoichiometric mixture of 2:1 YOCl (>98% tetragonal phase) and MgMn2O4 (spinel phase) was uniformly mixed and sealed in a quartz capillary. It was then heated in a gradient furnance, meaning that each location on the quartz tube had a different temperature31. The absolute temperatures at each point along the sample were calibrated from the lattice expansion of a known calibration material, Ni. The data went from a low temperature of 368∘C to a highest temperature of 668∘C with a total of 20 individual temperature points. Using ‘pyFAI’32, the collected 2D diffraction patterns were then cleaned by masking the beam-stop and over-bright/dead pixels, followed by an azimuthal integration to gain 1D PXRD patterns. The 1D PXRD data was then used as inputs to the different NMF algorithms." |
| 18 | +The data was originally sourced from: |
| 19 | +O’Nolan D, Huang G, Kamm GE, et al (2020) |
| 20 | +A thermal-gradient approach to variable-temperature measurements resolved in space. |
| 21 | +Journal of Applied Crystallography 53(3):662–670. |
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