Scattering Order

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danhsiu
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Scattering Order

Post by danhsiu » Wed May 05, 2021 9:13 am

Is the order of the value pairs for group-to-group scattering (INF_S0 & INF_SP0) incorrect per: https://serpent.vtt.fi/mediawiki/index. ... matrices_2?
Image where Image refers to scattering from group g to g'.
My understanding is that Serpent 2 transposed matrices, so the order would be Sigma(1,1) Self-fast scattering, Sigma(2,1) Down-Scattering, Sigma(1,2) Up-Scattering, and Sigma(2,2) Self-thermal scattering in a 2-group system. The reshaping commands would also be incorrect if true.

Is this correct?

Antti Rintala
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Re: Scattering Order

Post by Antti Rintala » Wed May 05, 2021 9:39 am

Your quotation and proposed correction are the same definition. You are just writing \Sigma_{g, g'} as Sigma(g',g).

danhsiu
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Re: Scattering Order

Post by danhsiu » Wed May 05, 2021 9:50 am

I could see that Antti. Isn't it more appropriate to write this in vector format?

Antti Rintala
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Re: Scattering Order

Post by Antti Rintala » Wed May 05, 2021 9:54 am

What do you mean exactly? The Serpent output is just a list of values, and during post-processing you can manipulate the order of the values as you like. The reshape command is an example how to obtain a matrix of the scattering values. It depends on the final usage whether this matrix is transposed or not.

danhsiu
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Re: Scattering Order

Post by danhsiu » Wed May 05, 2021 10:52 am

Thanks for the clarification. I was unclear on how energy groups are indexed in matrix outputs.

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