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Re: [ccp4bb]: problem with refmac5-TLS



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Just back off (very nice) holiday, but don't think I saw
a reply to this??

Basically, you get this error message if an atom has
an eigenvalue of U (anisotropic displacement parameter)
lower than a minimum value. If this eigenvalue is in
fact negative, then you have a non-physical U - a thermal
ellipsoid that's disappeared up its own principal axis ...

Normally, this is just a warning. The program adds an
isotropic component and continues. Subsequent cycles
may or may not converge to physical values.

Program TLSANL will generate U values and tell you which
are non positive definite.

However, -59 is very non-physical and suggests major
problems. What TLS values do you get? I guess incomplete
or incorrect model, in which case defer TLS until later.

Regards
Martyn


On Sat, 15 Jun 2002, Rafal Dolot wrote:

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> 
> 
> Hello,
> 
> I've a problem with refmac5. I use TLS refinement and after rebuilding
> model and start new refinement program stops work and give me information:
> 
> Problem in MAKE_U_POSITIVE  -59.93923
> 
> Where is a problem? Is it a problem with my structure?
> 
> Best regards
> 
> Rafal
> 
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> *                                                                 *
> *     Rafal Dolot                                                 *
> *                                                                 *
> * EMBL Hamburg Outstation            Technical University of Lodz *
> * c/o DESY, Notkestrasse 85   Institute of Technical Biochemistry *
> * D22603 Hamburg                              Stefanowskiego 4/10 *
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> 

**************************************************************************
*                                                                        *
*                  Dr. Martyn Winn                                       *
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