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6,272 bytes added ,  19 March 2011
Line 186: Line 186:


== Scaling ==
== Scaling ==
This is XSCALE.INP - we don't try anything fancy:
SPACE_GROUP_NUMBER=  22
UNIT_CELL_CONSTANTS=  156.80  163.12  595.87  90.000  90.000  90.000
OUTPUT_FILE=hr.ahkl
INPUT_FILE=../xds.hr1/XDS_ASCII.HKL
OUTPUT_FILE=pk.ahkl
INPUT_FILE=../xds.pk/XDS_ASCII.HKL
OUTPUT_FILE=ip.ahkl
INPUT_FILE=../xds.ip/XDS_ASCII.HKL
and this is an excerpt from XSCALE.LP:
      CORRELATIONS BETWEEN INPUT DATA SETS AFTER CORRECTIONS
DATA SETS  NUMBER OF COMMON  CORRELATION  RATIO OF COMMON  B-FACTOR
  #i  #j    REFLECTIONS    BETWEEN i,j  INTENSITIES (i/j)  BETWEEN i,j
    1    2      38920          0.986            1.0028        -0.1467
    1    3      36555          0.985            0.9971        0.2041
    2    3      35630          0.989            1.0038        -0.0116
These correlations are worse than what I like to see from MAD datasets. Some of the badness is maybe due to the fact that we used an unrealistic high-resolution limit. If we use INCLUDE_RESOLUTION_RANGE=50 3 the correlations are
The file further reports  CHI^2-VALUE OF FIT OF CORRECTION FACTORS around 1.15 which indicates that the scaling model is not entirely adequate, but it is unclear what to change, so we leave it at that (we could use STRICT_ABSORPTION_CORRECTION=TRUE to bring the number closer to 1).
Then we learn
******************************************************************************
    CORRECTION PARAMETERS FOR THE STANDARD ERROR OF REFLECTION INTENSITIES
******************************************************************************
The variance v0(I) of the intensity I obtained from counting statistics is
replaced by v(I)=a*(v0(I)+b*I^2). The model parameters a, b are chosen to
minimize the discrepancies between v(I) and the variance estimated from
sample statistics of symmetry related reflections. This model implicates
an asymptotic limit ISa=1/SQRT(a*b) for the highest I/Sigma(I) that the
experimental setup can produce (Diederichs (2010) Acta Cryst D66, 733-740).
Often the value of ISa is reduced from the initial value ISa0 due to systematic
errors showing up by comparison with other data sets in the scaling procedure.
(ISa=ISa0=-1 if v0 is unknown for a data set.)
    a        b          ISa    ISa0  INPUT DATA SET
6.329E+00  3.527E-04  21.17  22.36 ../xds.hr1/XDS_ASCII.HKL                         
7.255E+00  8.432E-04  12.79  13.43 ../xds.pk/XDS_ASCII.HKL                         
6.151E+00  6.548E-04  15.76  16.97 ../xds.ip/XDS_ASCII.HKL                         
which says that the high-remote indeed scales best of the three datasets, and the peak the worst. This is the output for high-remote - not too impressing!
******************************************************************************
  STATISTICS OF SCALED OUTPUT DATA SET : hr.ahkl                                         
  FILE TYPE:        XDS_ASCII      MERGE=FALSE          FRIEDEL'S_LAW=FALSE
      450 OUT OF    419653 REFLECTIONS REJECTED
    419203 REFLECTIONS ON OUTPUT FILE
******************************************************************************
...
      NOTE:      Friedel pairs are treated as different reflections.
SUBSET OF INTENSITY DATA WITH SIGNAL/NOISE >= -3.0 AS FUNCTION OF RESOLUTION
RESOLUTION    NUMBER OF REFLECTIONS    COMPLETENESS R-FACTOR  R-FACTOR COMPARED I/SIGMA  R-meas  Rmrgd-F  Anomal  SigAno
  Nano
  LIMIT    OBSERVED  UNIQUE  POSSIBLE    OF DATA  observed  expected                                      Corr
    12.39        5724    2008      2112      95.1%      2.5%      3.2%    5674  30.03    3.2%    2.3%    67%  1.522      850
    8.76      10864    3684      3837      96.0%      3.0%      3.5%    10807  26.32    3.7%    3.0%    62%  1.615    1649
    7.15      13926    4749      4984      95.3%      4.3%      4.3%    13862  21.17    5.3%    5.0%    47%  1.397    2149
    6.19      16773    5747      5895      97.5%      5.8%      5.6%    16708  16.66    7.1%    7.2%    30%  1.135    2664
    5.54      19099    6546      6690      97.8%      6.8%      6.5%    19008  14.51    8.4%    9.1%    24%  1.078    3041
    5.06      20933    7167      7374      97.2%      6.9%      6.7%    20828  14.04    8.6%    10.2%    17%  0.999    3321
    4.68      22497    7721      7993      96.6%      6.5%      6.2%    22372  14.51    8.1%    9.9%    15%  0.957    3564
    4.38      24415    8374      8666      96.6%      6.9%      6.6%    24280  13.74    8.5%    10.7%    12%  0.919    3870
    4.13      26251    8985      9164      98.0%      8.7%      8.4%    26113  11.47    10.7%    13.9%    8%  0.863    4203
    3.92      28037    9562      9686      98.7%      11.0%    10.8%    27878    9.38    13.5%    17.9%    6%  0.829    4485
    3.74      29520  10119    10241      98.8%      13.3%    13.4%    29337    7.75    16.4%    22.1%    6%  0.813    4746
    3.58      30822  10537    10662      98.8%      15.9%    15.9%    30639    6.74    19.6%    26.3%    8%  0.818    4933
    3.44      32336  11005    11104      99.1%      21.2%    21.6%    32151    5.20    26.0%    35.8%    5%  0.786    5164
    3.31      32608  11518    11593      99.4%      26.8%    27.5%    32195    4.07    33.1%    48.5%    3%  0.764    5248
    3.20      27228  11396    11998      95.0%      33.2%    34.5%    25691    2.79    42.5%    66.2%    4%  0.729    4287
    3.10      22192  10787    12431      86.8%      41.3%    43.7%    19573    1.94    54.3%    83.7%    1%  0.711    3403
    3.00      18768  10018    12806      78.2%      53.3%    56.5%    15662    1.49    71.6%  110.8%    -3%  0.669    2893
    2.92      15878    9250    13096      70.6%      67.6%    71.8%    12570    1.09    93.3%  141.2%    -1%  0.670    2408
    2.84      13496    8654    13568      63.8%      74.1%    78.5%    9579    0.88  104.4%  158.4%    1%  0.662    1796
    2.77        7836    6348    13844      45.9%      97.6%    103.5%    2966    0.58  137.9%  207.6%    1%  0.657    545
    total      419203  164175    187744      87.4%      10.2%    10.4%  397893    7.99    12.8%    24.6%    14%  0.882  65219


== Structure solution ==
== Structure solution ==
2,684

edits

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