Tuesday 6 December 2011

pointless problem

From: Ping Wang
Date: 2011/11/17


Dear all,

I have a dataset with spacegroup undetermined. When I use POINTLESS to determine laue group, the program gave the fatal error: HKLIN is merged and no HKLREF is defined, SPACEGROUP or REINDEX.

In the protocol of POINTLESS for the determination of LAUE group, HKLREF can be not specified. So I have no idea where the problem is. Can anyone give me some suggestions?

Kind regrads.

Ping



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From: Graeme Winter


Dear Ping,

You need the unmerged data for this - for instance the output from
Mosflm or the XDS INTEGRATE step. Pointless works by comparing
potentially symmetry related measurements.

Best wishes,

Graeme



----------
From: Graeme Winter


Hmm.... I am not sure about directly importing the .x files into
pointless, but you could run them through scalepack in P1 and write
out no merge original index, pointless can read that.

Best wishes,

Graeme


From: Tim Gruene
Dear all, dear Phil,

how can a dataset be merged if the space group is unknown? Does
pointless require the Friedel pairs present in the file, too?

Tim
- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4



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From: Eleanor Dodson


Aaagh - you merge the POINT group!!!!!
Not the spacegroup...


Eleanor

----------
From: Eleanor Dodson

It doesn't matter about running scalepack in P1 - just set the nomerge
option and read that sca file into pointless.

Infuriationly - that file does NOT have the cell or the wavelength in
the header so you have to add that by hand in the GUI
Eleanor

----------
From: Tim Gruene


Dear Eleanor,

Sorry, but I don't see how your comment answers any of my two questions.

Tim

----------
From: Phil Evans


Pointless will do the best it can with whatever data you give it, but if it is already merged then it can only check for under-merging, or for reindexing

The normal use is for unmerged data as output by an integration program such as Mosflm or XDS, as a prelude for scaling with Aimless or Scala. It that case Friedel pairs will be present.

Phil


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