[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*To*:*Multiple recipients of list <coredmg@iucr.org>***Subject**:**Re: Expressions for R factors****From**:**"George M. Sheldrick" <gsheldr@shelx.uni-ac.gwdg.de>***Date*:*Fri, 4 Sep 1998 14:39:38 +0100 (BST)**Reply-To*:*coredmg@iucr.org*

Dear Brian My programs have always used Y(obs) in the denominator, so either (a) it is a typo in the dictionary, or (b) the majority of the CIFs in the Acta database are wrong. Which would you prefer ? Best wishes, George ======================================================================== Brian McMahon wrote: > > John Bollinger at Indiana writes: > > > With regard to _refine_ls_wR_factor_*: it seems unusual to me that the > > sum in the denominator is over Y(calc) instead of over Y(obs). Is this > > intentional, and if so, can you refer me to any literature about why this > > particular usage is to be preferred? I have never run into it before, and I > > shall have to make special provisions to get my software to calculate it. I > > see that this formula appears in the version 2.0.1 dictionary as well, but > > that does not invalidate the question. > > For example, the definition of _refine_ls_wR_factor_all is > > ( sum | w | Y(obs) - Y(calc) |^2^ | )^1/2^ > wR = ( --------------------------------- ) > ( sum | w Y(calc)^2^ | ) > > as against the definition for _refine_ls_R_factor_gt, which is > > sum | F(obs) - F(calc) | > R = ------------------------ > sum | F(obs) | > > I note that the original definition for _refine_ls_wR_factor_ in version 1.0 > of the Core read > > wR = [sum(w|Ym-Yc|^2^) / sum(wYm^2^)]^1/2^ > > Have we simply introduced a typo into later versions? > > Brian

- Prev by Date:
**Expressions for R factors** - Next by Date:
**Re: Transfer from msCIF: refine_ls_class category** - Prev by thread:
**Expressions for R factors** - Next by thread:
**Re: Expressions for R factors** - Index(es):

**Copyright © International Union of Crystallography**