Thank you, Eleanor!
I'll try pointless. In my case, the Sigma increase as i merge all the
five data while I/sigma decrease, which is opposite to what you
describe. Is this abnormal?
Fengyun
Quoting Eleanor Dodson <[log in to unmask]>:
> All this is best done from the GUI - pointless will sort out batch
> numbers, check indexing etc..
> But you still have to identify any rogue batches, and decide on when
> to jettison the data st..
> The Sigma level is related to the number of observations of each
> reflection, so this will decrease as the number of observations
> increases, and therefor I/Sigma will increase..
>
> Eleanor
> On 16 Jul 2012, at 14:54, Fengyun Ni wrote:
>
>> Hi all,
>>
>> I have to merge several datasets from different crystals because
>> the crystals suffer from severe radiation damage.
>>
>> I read some previous posts and follow the protocol as described,
>> 1) individually process the data;
>> 2) scaleit to compare the Rfactors between different datasets;
>> 3) renumber the batch number;
>> 4) for those with low R-factor files (below 0.25), sort them;
>> 5) scala the sorted file.
>>
>> the script i used for the SCALA is,
>> scales batch brotaion spacing 5
>>
>> which is the one in CCP4 example script that recommended for
>> synchrontron data.
>>
>> For the first four dataset that are all cutoff to about 3.0A based
>> on I/sigI, and the statistics are like this,
>>
>>
>> N 1/d^2 Dmin(A) Rmrg Rfull Rcum Av_I SIGMA I/sigma
>> $$
>> 1 0.0111 9.49 0.038 0.030 0.038 1934 125.2 15.5
>> 2 0.0222 6.71 0.050 0.009 0.044 1182 92.4 12.8
>> 3 0.0333 5.48 0.086 0.018 0.055 565 71.0 8.0
>> 4 0.0444 4.74 0.093 0.166 0.065 724 100.2 7.2
>> 5 0.0556 4.24 0.105 0.139 0.074 746 116.9 6.4
>> 6 0.0667 3.87 0.143 0.058 0.085 522 105.4 5.0
>> 7 0.0778 3.59 0.217 0.142 0.098 358 107.8 3.3
>> 8 0.0889 3.35 0.365 0.265 0.115 216 109.5 2.0
>> 9 0.1000 3.16 0.634 2.509 0.134 126 110.0 1.1
>> 10 0.1111 3.00 0.965 10.157 0.154 81 109.8 0.7
>>
>>
>>
>> For the fifth data cutoff to 2.76A, the stastics for the single
>> data is like this,
>>
>>
>> N 1/d^2 Dmin(A) Rmrg Rfull Rcum Av_I SIGMA I/sigma
>> $$
>> 1 0.0131 8.73 0.031 0.036 0.031 6866 416.2 16.5
>> 2 0.0263 6.17 0.034 0.036 0.032 2994 185.5 16.1
>> 3 0.0394 5.04 0.039 0.040 0.034 2327 185.5 12.5
>> 4 0.0525 4.36 0.039 0.045 0.036 3358 249.6 13.5
>> 5 0.0656 3.90 0.047 0.048 0.038 2226 184.2 12.1
>> 6 0.0788 3.56 0.064 0.059 0.041 1390 151.7 9.2
>> 7 0.0919 3.30 0.101 0.084 0.045 787 118.0 6.7
>> 8 0.1050 3.09 0.145 0.114 0.048 482 98.8 4.9
>> 9 0.1181 2.91 0.271 0.234 0.053 259 96.5 2.7
>> 10 0.1313 2.76 0.398 0.333 0.058 183 102.8 1.8
>>
>>
>> Then i merge this fifth data with the other four and get the
>> stastics like this,
>>
>>
>> N 1/d^2 Dmin(A) Rmrg Rfull Rcum Av_I SIGMA I/sigma
>> $$
>> 1 0.0131 8.73 0.072 0.048 0.072 7545 954.4 7.9
>> 2 0.0263 6.17 0.100 0.057 0.085 3417 528.8 6.5
>> 3 0.0394 5.04 0.145 0.072 0.103 2497 543.6 4.6
>> 4 0.0525 4.36 0.158 0.089 0.121 3308 790.6 4.2
>> 5 0.0656 3.90 0.200 0.091 0.138 2374 710.3 3.3
>> 6 0.0788 3.56 0.299 0.128 0.158 1496 663.8 2.3
>> 7 0.0919 3.30 0.462 0.173 0.177 848 644.7 1.3
>> 8 0.1050 3.09 0.577 0.144 0.187 483 414.7 1.2
>> 9 0.1181 2.91 0.720 0.265 0.192 311 358.2 0.9
>> 10 0.1312 2.76 0.392 0.342 0.192 217 122.7 1.8
>>
>>
>> My question is that after why the SIG_I becomes very large at
>> different resolution shells merging the five data. Say, at 8.73A,
>> merging the four low-resolution files give about SIG_I of 125; the
>> single high-resolution file give 416, but after merging, they give
>> up to 954, is this normal? or i made something wrong?
>>
>> Thank you very much in advance!
>> Fengyun
>
>
>
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