Changing powder averaging methods

[mjunior-NMR]

Dear MRSimulator developers and community,
I would like to have more information about which method of powder averaging MRSimulator is using to create powder patterns. Also, I want to know if (and how) it would be possible for the user to change these methods for specific simulations.
Thank you very much,
Marcos Oliveira.

[deepanshs]

Hi Marcos,

Mrsimulator uses Alderman and Grant's approach of octahedron sampling and interpolation (https://doi.org/10.1063/1.450211). The two parameters that generate this sampling pattern are integration_volume and integration density. These parameters are described in the doc.

In the current version, it is not possible to change the powder averaging method, but it is possible to include it in a future version. You can submit a feature request in the feature request section.

Best,
Deepansh

[mjunior-NMR]

Dear Deepansh, thank you very much for your attention. It was really helpful. If you could answer one other question I would appreciate a lot. Do you know how the eps parameter in the extended Czjzek model in MRSilmulator relates to the sigma parameter in ssnake? Thank you very much, Marcos. -- Prof. Dr. Marcos de Oliveira Junior Grupo de Ressonância Magnética, Espectroscopia e Magnetismo Instituto de Física de São Carlos, Universidade de São Paulo (IFSC/USP) Av. Trabalhador Sãocarlense 400, 13566-590, São Carlos - SP, Brasil Sala 19 - Bloco F2 - 1º andar Em qua., 29 de nov. de 2023 às 13:03, Deepansh Srivastava < ***@***.***> escreveu:

…

Hi Marcos, Mrsimulator uses Alderman and Grant's approach of octahedron sampling and interpolation (https://doi.org/10.1063/1.450211). The two parameters that generate this sampling pattern are integration_volume and integration density. These parameters are described in the doc <https://mrsimulator.readthedocs.io/en/stable/user_guide/simulator/simulator.html#integration-density> . In the current version, it is not possible to change the powder averaging method, but it is possible to include it in a future version. You can submit a feature request in the feature request <https://github.com/deepanshs/mrsimulator/issues/new?assignees=&labels=type%3AEnhancement&projects=&template=FEATURE_REQUEST.md&title=> section. Best, Deepansh — Reply to this email directly, view it on GitHub <#305 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ATM3BJUK4HNZ6UFDE6H4OP3YG5MGTAVCNFSM6AAAAAA77SD2XKVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM3TOMBWGY3TQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[deepanshs]

Dear Marcos,

We have documented the parameter eps in the docs. The original definition is from Caer et. al., Eq. 10. According to this definition, $\rho$ (which is parametrically dependent on $\epsilon$ eps) is the standard deviation of the multivariate Gaussian, the same as the $\sigma$ parameter from ssnake.

Please note that this assessment is based on the definition of standard deviations from Meerten et. al. and Caer et. al.. I haven't compared and verified it with simulation. If you do verify simulations, please share your findings with us.

Thank you,
Deepansh

[mjunior-NMR]

Dear Deepansh, I am currently in a conference. As soon as I get back to the office, I send you an example. Best regards, Marcos. -- Prof. Dr. Marcos de Oliveira Junior Grupo de Ressonância Magnética, Espectroscopia e Magnetismo Instituto de Física de São Carlos, Universidade de São Paulo (IFSC/USP) Av. Trabalhador Sãocarlense 400, 13566-590, São Carlos - SP, Brasil Sala 19 - Bloco F2 - 1º andar Em seg., 4 de dez. de 2023 às 15:27, Deepansh Srivastava < ***@***.***> escreveu:

…

Dear Marcos, We have documented the parameter eps in the docs <https://mrsimulator.readthedocs.io/en/latest/theory/models.html#extended-czjzek-distribution>. The original definition is from Caer et. al. <https://doi.org/10.1088/0953-8984/22/6/065402>, Eq. 10. According to this definition, $\rho$ (which is parametrically dependent on $\epsilon$ eps) is the standard deviation of the multivariate Gaussian, the same as the $\sigma$ parameter from ssnake. Please note that this assessment is based on the definition of standard deviations from Meerten et. al. <https://www.sciencedirect.com/science/article/pii/S1090780719300308#b0065> and Caer et. al. <https://doi.org/10.1088/0953-8984/22/6/065402>. I haven't compared and verified it with simulation. If you do verify simulations, please share your findings with us. Thank you, Deepansh — Reply to this email directly, view it on GitHub <#305 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ATM3BJTECGSOWL7SPEXEEDLYHYIYBAVCNFSM6AAAAAA77SD2XKVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM3TONJWGM2TI> . You are receiving this because you authored the thread.Message ID: ***@***.***>