XmlmmCIF equivalent: refine_analyze
Data items in the REFINE_ANALYZE category record details
about the refined structure that are often used to analyze the
refinement and asses its quality. A given computer program
may or may not produce values corresponding to these data
names.
XmlmmCIF equivalent: refine_analyze/Luzzati_coordinate_error_free
The estimated coordinate error obtain from the plot of
the R value versus sin(theta)/lambda for the reflections
treated as a test set in refinement.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_coordinate_error_obs
The estimated coordinate error obtained from the plot of
the R value versus sin(theta)/lambda for reflections classified
as observed.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_d_res_low_free
The value of the low resolution cutoff used in constructing the
Luzzati plot for reflections treated as a test set in
refinement.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_d_res_low_obs
The value of the low resolution cutoff used in
constructing the Luzzati plot for reflections classified as
observed.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_sigma_a_free
The value of sigma~a~ used in constructing the Luzzati plot for
the reflections treated as a test set in refinement. The
details of the estimation of sigma~a~ can be specified
in _refine_analyze.Luzzati_sigma_a_free_details.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_sigma_a_free_details
The details of the estimation of sigma~a~ for the reflections treated as a test set in refinement.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_sigma_a_obs
The value of sigma~a~ used in constructing the Luzzati plot for
reflections classified as observed. The details of the estimation of sigma~a~ can be specified in
_refine_analyze.Luzzati_sigma_a_obs_details.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/Luzzati_sigma_a_obs_details
Special aspects of the estimation of sigma~a~ for the reflections classified as observed.
Ref: Luzzati, V. (1952). Acta Cryst. 5, 134-136.
XmlmmCIF equivalent: refine_analyze/RG_d_res_high
The value of the high-resolution cutoff in angstroms used in calculation of the Hamilton generalized
R factor (RG) stored in refine_analyze.RG_work and _refine_analyze.RG_free.
Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.
XmlmmCIF equivalent: refine_analyze/RG_d_res_low
The value of the low-resolution cutoff in angstroms used in calculation of the Hamilton generalized
R factor (RG) stored in refine_analyze.RG_work and _refine_analyze.RG_free.
Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.
XmlmmCIF equivalent: refine_analyze/RG_free
The Hamilton generalized R factor for all reflections that
satisfy the resolution limits established by _refine_analyze.RG_d_res_high and
_refine_analyze.RG_d_res_low for the free R set of reflections that were excluded from the refinement.
sum_i sum_j w_{i,j}(|Fobs|_i - G|Fcalc|_i)(|Fobs|_j - G|Fcalc|_j)
Rg = Sqrt( ----------------------------------------------------------------------------------------------------- )
sum_i sum_j w_{i,j} |Fobs|_i |Fobs|_j
where
|Fobs| = the observed structure factor amplitudes
|Fcalc| = the calculated structure factor amplitudes
G = the scale factor which puts |Fcalc| on the same scale as |Fobs|
w_{i,j} = the weight for the combination of the reflections i and j.
sum_i and sum_j are taken over the specified reflections
When the covariance of the amplitude of reflection i and reflection j is zero (i.e. the reflections are independent)
w{i,i} can be redefined as w_i and the nested sums collapsed
into one.
sum_i w_i(|Fobs|_i - G|Fcalc|_i)^2
Rg = Sqrt( ---------------------------------------------------- )
sum_i w_i |Fobs|_i^2
Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.
XmlmmCIF equivalent: refine_analyze/RG_free_work_ratio
The observed ratio of RGfree to RGwork. The expected RG ratio
is the value that should be achievable at the end of a structure
refinement when only random uncorrelated errors exist in data
and model provided that the observations are properly weighted.
When compared with the observed RG ratio it may indicate that a
structure has not reached convergence or a model has been
over-refined with no corresponding improvement in the model.
In an unrestrained refinement the ratio of RGfree/RGwork with
only random uncorrelated errors at convergence depends only
on the number of reflections and the number of parameters as:
sqrt[(f + m) / (f - m) ]
where
f = number of included structure amplitudes and target distances, and
m = number of parameters being refined.
In the restrained case, RGfree is calculated from a random
selection of residuals including both structure amplitudes
and restraints. When restraints are included in refinement
the RG ratio requires a term for the contribution to the
minimized residual at convergence, Drest, due to those
restraints:
Drest = r - sum (w_i . (a_i)^t . (H)^-1 a_i
where
r is the number of geometrical, temperature factor and
other restraints
H is the (m,m) normal matrix given by A^t.W.A
W is the (n,n) symmetric weight matrix of the included
observations
A is the least-squares design matrix of derivatives of
order (n,m)
a_i is the ith row of A
Then the expected RGratio becomes
sqrt [ (f + (m - r + Drest))/ (f - (m - r + Drest)) ]
The expected RGfree/RGwork is not yet included in the mmCIF
dictionary.
Ref: "Rfree and the Rfree ratio. Part I: derivation of expected
values of cross-validation residuals used in macromolecular least-squares refinement".
Tickle, I. J., Laskowski, R. A. and Moss, D.S. (1998). Acta Cryst. D, in the press.
XmlmmCIF equivalent: refine_analyze/RG_work
The Hamilton generalized R factor for all reflections
that satisfy the resolution limits established by
_refine_analyze.RG_d_res_high and
_refine_analyze.RG_d_res_low and for those
reflections included in the working set when a free R set of reflections are omitted from the refinement.
sum_i sum_j w_{i,j}(|Fobs|_i - G|Fcalc|_i)(|Fobs|_j - G|Fcalc|_j)
Rg = Sqrt( ---------------------------------------------------------------------------------------------- )
sum_i sum_j w_{i,j} |Fobs|_i |Fobs|_j
where
|Fobs| = the observed structure factor amplitudes
|Fcalc| = the calculated structure factor amplitudes
G = the scale factor which puts |Fcalc| on the
same scale as |Fobs|
w_{i,j} = the weight for the combination of the reflections i and j.
sum_i and sum_j are taken over the specified reflections
When the covariance of the amplitude of reflection i and
reflection j is zero (i.e. the reflections are independent)
w{i,i} can be redefined as w_i and the nested sums collapsed
into one.
sum_i w_i(|Fobs|_i - G|Fcalc|_i)^2
Rg = Sqrt( --------------------------------------------------------------------------------------- )
sum_i w_i |Fobs|_i^2
Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.
XmlmmCIF equivalent: refine_analyze/number_disordered_residues
The number of discretely disorded residues in the refined model.
XmlmmCIF equivalent: refine_analyze/occupancy_sum_hydrogen
The sum of the occupancies of the hydrogen atoms in the refined
model.
XmlmmCIF equivalent: refine_analyze/occupancy_sum_non_hydrogen
The sum of the occupancies of the non-hydrogen atoms in the
refined model.
XmlmmCIF equivalent: refine_analyze/entry_id
This data item is a pointer to _entry.id in the ENTRY category.