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# https://iso.byu.edu/iso/findssghelp.php
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# The output notation for superspace-group operators will match that of the input: There are three choices: (x,y,z,t,u,v), (x1,x2,x3,x4,x5,x6), and (xs1,xs2,xs3,xs4,xs5,xs6). See the ISO(3+d)D help page for more information about these notations.
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- # Define variable-length `Indeterminate's in function.
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- # https://mail.google.com/mail/u/0/?ogbl#search/in%3Asent+gap/QgrcJHsBqxpXbHCSnPqBGGBZRDqphmxvpZb
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InstallGlobalFunction( IdentifyGroupGenerators, function ( S )
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local gens, vecname, d, vec, g, i;
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- # BCS IDENTIFY GROUP 和 findssg 都是工作于左作用下面的标准表示的 。
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+ # BCS IDENTIFY GROUP 和 findssg 都是工作于左作用下的标准表示的 。
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if IsAffineCrystGroupOnRight(S) then
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S:= TransposedMatrixGroup(S);
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fi ;
@@ -374,10 +372,11 @@ end );
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# return apar;
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# end );
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- # Find the highest finite order group element of an infinite group.
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- # https://mail.google.com/mail/u/0/?ogbl#sent/KtbxLwHLtgJlPSGRwNfgCnBVmRxJDfvqdV
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- # The highest finite order of an element of your group is 6, cf. https://en.wikipedia.org/wiki/Crystallographic_restriction_theorem .
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+
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+ # The highest finite order of an element of your group is 6, cf. https://en.wikipedia.org/wiki/Crystallographic_restriction_theorem.
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+ # Find the highest finite order group element of an infinite group.
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# Hope this helps,
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# Stefan
@@ -892,11 +891,7 @@ InstallGlobalFunction( AffineIsomorphismSpaceGroups, function( S1, S2 )
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end );
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- # About my research results on the minimal generating set of space groups and my thanks to you.
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- # https://mail.google.com/mail/u/0/?ogbl#drafts/KtbxLwHDlCCBldrFJCXLMDsMVGZBLcklzL
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-
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# Ask for your comments and suggestions about my implementation of the MinimalGeneratingSetAffineCrystGroup.
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- # https://mail.google.com/mail/u/0/?ogbl#inbox/QgrcJHsHqgRmwLtpXtLbsrWKXXWRXfgncNL
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# Dear Zhao,
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# well -- the minimal generating set problem for infinite non-nilpotent groups
@@ -1106,7 +1101,7 @@ ConjugatorSpaceGroupEnantiomorphicPartner, function( S )
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d:= DimensionOfMatrixGroup(S) - 1 ;
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- # 再调用 CARAT 的相关程序之前,首先用下面的方法来彻底简化已给空间群的表示:
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+ # 在调用 CARAT 的相关程序之前,首先用下面的方法来彻底简化已给空间群的表示:
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CS:= ConjugatorSpaceGroupSimplification(S);
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S:= S^ (CS^- 1 );
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P:= PointGroup(S);
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# Add the function DirectSumDecompositionMatrix.
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# https://github.com/gap-packages/utils/issues/64#issuecomment-1591422710
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- # Direct sum decomposition of a matrix.
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- # https://mail.google.com/mail/u/0/?ogbl#sent/KtbxLwHHpRfqHzrslftpfCbXhvQJngJvxV
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- # Dear forum,
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# This is a possible approach, inspired in
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# https://github.com/gap-packages/numericalsgps/blob/fcde379b01bd44b1fa80cd69d7ddd6a8acdcfe2f/gap/catenary-tame.gi#LL803C1-L831C4
@@ -1239,12 +1231,6 @@ DirectSumDecompositionMatrix, function(l)
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end );
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- # About the three classes translations related to a specific space group.
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- # https://mail.google.com/mail/u/0/?ogbl#search/branton%40byu.edu+origin+shift+/QgrcJHsbjCgGxkTcpwdpcRTMdWjmWTPHncg
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-
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- # Some further discussions based on your lecture note "Group theory applied to crystallography" and some of your papers.
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- # https://mail.google.com/mail/u/0/?ogbl#sent/KtbxLvHgMkZlGBgrVFcHgjClrgRRwWDdtg
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-
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# Bernd Souvignier的 lecture note,page 27, Theorem 43:
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# https://www.math.ru.nl/~souvi/krist_09/cryst.pdf
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# The following theorem (which is not hard to prove) states that by an appropriate shift of the
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# 2. 若首先转到标准表示,再进行基于LLLReducedGramMat的简化方法,则可以保证结果仍是标准表示,便于后续进一步简化矢量系统。
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# 故改为基于LLReducedGramMat的方法
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- # 3. 基于 Theorem 43,有理化矢量系统。
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+ # 3. 基于Bernd Souvignier的 lecture note 中的 Theorem 43,有理化矢量系统。
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# 确保返回一个保手性的conjugator,这样才不会改变晶体学意义上的空间群类型。
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# However, groups that differ only by their orientation are closely related to each other and share
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# many properties. One addresses this phenomenon by the concept of enantiomorphism.
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-
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- # 算法的进一步优化的可能性:
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- # 1. 基于 GroupSumBSGS 思想高效计算 Sum(trans)
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- # 2. InternalBasis 高效实现。
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-
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# 用下面的解决方法来首先彻底简化已给空间群的表示:
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InstallGlobalFunction(
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ConjugatorSpaceGroupSimplification, function ( S )
@@ -1317,8 +1298,7 @@ ConjugatorSpaceGroupSimplification, function( S )
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llg:= LLLReducedGramMat(F);
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- # https://mail.google.com/mail/u/0/?ogbl#search/enantiomorphic+pair+conjugator/QgrcJHrtvXrNdzwRxSLnPpGBpgpLbrmxVnb
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- # To have a standard orientation-reversing operation in arbitrary
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+ # To have a standard orientation-reversing operation in arbitrary
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# dimension, one would indeed take a transformation with an odd number of
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# elements -1 and the rest 1, but the simplest odd number is 1, so one
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# would take a matrix with just one -1 and the rest 1, this is simply a
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