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Question: representation of uncertainties in scientific notation

  • Subject: Question: representation of uncertainties in scientific notation
  • From: "Brian H. Toby" <Brian.Toby@xxxxxxxx>
  • Date: Thu, 1 Aug 2002 16:29:56 +0100 (BST)
Hi, 

   Does anyone know how CIF handles numbers with "esd's" when they are
in exponential notation, (at least for DLL 1.x, where numbers may be
reported as -12.345(2) if the esd flag is true.)

   My understanding is the conventional crystallographic notation for a
number in exponential notation is 

	-1.2345(2) x 10^1

but my reading of section 59 in
http://www.iucr.org/iucr-top/cif/developers/spec/cifsyntax.html 
is that CIF uses 

	-1.2345e1(2)

I just want to check that -1.2345(2)e1 is not valid and has never been
intended to valid in CIF.

Brian
 
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Brian H. Toby, Ph.D.                    Leader, Crystallography Team
Brian.Toby@NIST.gov      NIST Center for Neutron Research, Stop 8562
voice: 301-975-4297     National Institute of Standards & Technology
FAX: 301-921-9847                        Gaithersburg, MD 20899-8562
                http://www.ncnr.nist.gov/xtal
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