<div dir="auto"><div><div>This is almost certainly related to numerical precision. There are so e partial cures for this in code that traps 1/3 and 2/3 for hexagonal, but it is not complete and there are some numerical issues with the rotation matrices as well; you can look at SymmRot.f in SRC_lapw0. It probably needs expansion and use in more areas, which is not a 1 minute fix.</div><div dir="auto"><br></div><div dir="auto">Two patches may work:</div><div dir="auto">1) use "init_lapw ....-s sgoup" to skip symmetry</div><div dir="auto">2) generate the Symm using a smaller cell than paste those onto the end of the struct file. Maybe also use x patchsymm as well. You may still need to do 1!</div><div><br></div><div data-smartmail="gmail_signature">___<br>Emeritus Professor Laurence Marks (Laurie)<br>Department of Materials Science and Engineering, Northwestern University<br><a href="http://www.numis.northwestern.edu">www.numis.northwestern.edu</a><br>"Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi</div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, May 29, 2026, 18:08 Gavin Abo <<a href="mailto:gabo13279@gmail.com">gabo13279@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div>
<p>Seems like it could be related to numerical precision. Taking
the test2.struct that you sent, I also see the "2 missing" with
WIEN2k 24.1 for Y=0.66666666 for ATOM 74 and 98, but it seems to
go away if Y=0.66666667 is used:</p>
<p>username@computername:~/wiendata/test2$ grep "ATOM 74"
test2.struct<br>
ATOM 74: X=0.33333333 Y=0.66666666 Z=0.70000000<br>
username@computername:~/wiendata/test2$ grep "ATOM 98"
test2.struct<br>
ATOM 98: X=0.33333333 Y=0.66666666 Z=0.50000000<br>
username@computername:~/wiendata/test2$ x symmetry<br>
SPACE GROUP DOES NOT CONTAIN INVERSION<br>
STOP 2 missing <br>
0.141u 0.011s 0:00.15 100.0% 0+0k 0+664io 0pf+0w</p>
<p>username@computername:~/wiendata/test2$ gedit test2.struct<br>
username@computername:~/wiendata/test2$ grep "ATOM 74"
test2.struct<br>
ATOM 74: X=0.33333333 Y=0.66666667 Z=0.70000000<br>
username@computername:~/wiendata/test2$ grep "ATOM 98"
test2.struct<br>
ATOM 98: X=0.33333333 Y=0.66666667 Z=0.50000000<br>
username@computername:~/wiendata/test2$ x symmetry<br>
SPACE GROUP DOES NOT CONTAIN INVERSION<br>
0.190u 0.010s 0:00.20 100.0% 0+0k 0+728io 0pf+0w</p>
<p>Kind Regards,</p>
Gavin<br>
WIEN2k user
<div><br>
</div>
<div>On 5/29/2026 2:57 AM, Stefaan Cottenier
via Wien wrote:<br>
</div>
<blockquote type="cite">
<div style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<span style="color:rgb(200,38,19)">(I'm re-sending this
message, as the attached struct file in my previous post was
too large. Now it's gzipped and smaller)</span></div>
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<br>
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<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
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Dear WIEN2k developers,</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
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I ran into an issue that is probably a communication problem
between sgroup and symmetry. The attached struct file is a large
supercell (Ag substitutional impurity in hcp-Zn), that has been
created by sgroup as space group P-6 with 102 inequivalent
positions. </div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
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When running 'x symmetry' in a folder that contains only this
struct file, it fails for the 18<sup>th</sup> inequivalent
position (Zn17):</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
ATOM 18: X=0.33333333 Y=0.66666666 Z=0.10000000</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
MULT= 2 ISPLIT= 8</div>
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18: X=0.33333333 Y=0.66666666 Z=0.90000000</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
Zn17 NPT= 781 R0=0.00005000 RMT= 2.3700 Z: 30.0</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
0.0000000 1.0000000 0.0000000</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
0.0000000 0.0000000 1.0000000</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
The last lines of case.outputs read:</div>
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<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
ATOM: 18</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
Zn17 operation # 1 1</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
Zn17 operation # 22 3 || -z</div>
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pointgroup is 2 (neg. iatnr!!)</div>
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axes should be: 2 || z</div>
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<br>
</div>
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Both case.struct_st and case.in2_sy (that are produced by 'x
symmetry') are truncated after the 17<sup>th</sup> inequivalent
position. The screen output is:</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
SPACE GROUP DOES NOT CONTAIN INVERSION</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
2 missing</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
0.010u 0.003s 0:00.01 100.0% 0+0k 0+0io 0pf+0w</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
It looks like symmetry finds a point group "2", and does not
recognize that one.</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
Not sure whether the problem is in sgroup, in symmetry, or in
the way how they communicate to each other. </div>
<div style="direction:ltr;font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)">
<br>
</div>
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This was done with version 24.1. Any suggestion how to fix this?</div>
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<br>
</div>
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Best regards,</div>
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Stefaan</div>
</blockquote>
</div>
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