[Wien] Error in det_lat_NSM(): the special conditions not satisfied

[Peter Blaha]

I checked these cif files.   Where are they from ? How are they created ?

They might be formally "correct", but at least I've never seen regular
definitions of P1 structures with lattice parameters like:

_cell_length_a                   26.1349
_cell_length_b                   25.1482
_cell_length_c                   13.3073
_cell_angle_alpha                19.11
_cell_angle_beta                 10.89
_cell_angle_gamma                22.52
_symmetry_space_group_name_H-M   'P1'

Most of your structures work anyway with x nn and x symmetry, sgroup is not
useful in your cases anyway.

When problems occur, this is probably because some positions like 0.33333 are
"truncated" and should be set with full accuracy.

In any case, I cannot support problems due to such "unusual" structures.

Am 01.02.2012 07:50, schrieb Peter Blaha:
> I need a specific case.struct file and the corresponding error.
>
> Presumable all (most) of your struct files are wrong.
>
> "tolerance problem": usually it means that your positions in case.struct are not
> "accurate". This happens typically for truncated 1/3 or 1/6; or sometimes it is just
> "rounding errors" in the last digit, which should be corrected.
>
>
> Am 31.01.2012 15:00, schrieb Ghosh SUDDHASATTWA:
>> Dear Wien2k users,
>>
>> I have been working on a monoclinic system. I tried to find equivalent structures using the Bilbao Crystallographic Server. One of the structures generated gives the
>> following error when I do init_lapw from command line ( not from w2web) (latest version of Wien2k is being used).
>>
>>> sgroup (19:25:19) Error in det_lat_NSM(): the special conditions not sa
>>
>> tisfied.
>>
>> Try to change TOL parameter defined in type_sg.h,or it may be a bug in the progr
>>
>> am :-(
>>
>> Accuracy problem. Please run with different tolerance (x sgroup -settol .0000010
>>
>> 0)
>>
>> Error in det_lat_NSM(): the special conditions not satisfied.
>>
>> Try to change TOL parameter defined in type_sg.h,or it may be a bug in the progr
>>
>> am :-(
>>
>> 0.000u 0.001s 0:00.00 0.0% 0+0k 0+0io 0pf+0w
>>
>> error: command /home/appl/wien2k/sgroup -wi test.struct -wo test.struct_sgroup
>>
>> -set-TOL=0.00001 failed
>>
>> Another structure gives error during x symmetry
>>
>>> symmetry (19:28:51) alpha(3) .lt. 89.8; reset to 90.1
>>
>> ERROR: negative position in rstruc. Please report
>>
>> Moreover, the unusual thing about this rstruc error is that it always comes when I work with a monoclinic system with a composition AB2 type.
>>
>> I am not sure if the problem is related to the rstruc problem I discussed before after which Dr. Blaha had posted a revised subroutine.
>>
>> Any suggestions please
>>
>> Regards
>>
>> Suddhasattwa
>>
>>
>>
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>

-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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