Re: [ccp4bb]: FreeRflag in mtz2various

["Sergei V. Strelkov" <Sergei-V.Strelkov@unibas.ch>]

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Dear Joao,

mtz2various indeed (if I remember it right) does not change the 'free'
column, i.e. what was FreeRflag=0 in mtz file gets TEST=0.

Yes, ccp4 uses FreeRflag=0 for the 'free' set,
and the default XPLOR/CNS way is to use 1.

However, you can easily change this by selecting
{===>} test_flag=0;
whithin every CNS input file you use.

My preferred way is to use the ccp4 convention
while using both ccp4 and CNS, to avoid
confusion when you switch from one to the other.

Sergei.


> ***  For details on how to be removed from this list visit the  ***
> ***          CCP4 home page http://www.ccp4.ac.uk         ***
>
> Dear all,
>
> I tried converting a mtz file with freeRflags assigned to CNS format using
> mtz2various.
>
> mtzdump of input.mtz file:
>   -31   1   2   ...     1.00
>   -31   1   4   ...     1.00
>   -31   3   1   ...     0.00
>
> output.hkl generated with mtz2various (OUTPUT CNS):
>  INDE   -31    1    2 FOBS=      70.8       0.0 SIGMA=      7.52 TEST=     1
>  INDE   -31    1    4 FOBS=      42.1       0.0 SIGMA=     14.77 TEST=     1
>  INDE   -31    3    1 FOBS=      37.5       0.0 SIGMA=     13.61 TEST=     0
>
> In the manual pages for mtz2various, we are directed to look at the freerflag
> page where the following comments are made:
>
>        Convention for free and working set flags:
>  CCP4 assigns the flag FreeR_flag to be 0 for the free set and 1,...n-1 for the
> working set.
>  CNS  assigns the flag TEST to be 1 for the free set and 0,2,...n-1 for the
> working set.
>
> It may sound obvious, but I want the same (free) set of reflection to be left
> out of the refinement if I am using refmac or CNS. So the TEST=1 should appear
> for the reflections with FreeR_flag=0 in the mtz file and viceversa. Is this a
> bug or we are supposed to swap the ones and zeros ourselves?
>
> PS.: I tried using the keyword FREEVAL with values 1 and 0, but there were no
> changes on the output.
>
> Thank you, joao.

--
Sergei V. Strelkov, Ph.D.                 Tel. ++41 61 267 2091 (lab)
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