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<p class="MsoPlainText">Hello,<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><span lang="EN-US">Continuing and confirmating Pavel’s last comments:
<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText" style="text-indent:35.4pt"><span lang="EN-US">yes, we saw a number of practical cases when non-uniformly distributed missed data, even a small percent, caused great map distortions (some example are listed in our manuscript recently
submitted to J.Appl.Cryst). To track this situation, recently we have developed a small python-based program that starting from your MTZ file searches for connected regions of such unmeasured reflections, gives their characteristics and visualizes the regions
on the user’s request. Presence of such regions may make your maps ugly even when the phases are perfect.<o:p></o:p></span></p>
<p class="MsoPlainText" style="text-indent:35.4pt"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"> For an official release when ready the program will be available at the Web site of the institute; for a time being if you want to test the current version please send me a mail to
<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US">sacha@igbmc.fr<br>
<br>
<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><br>
With best regards,<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText">Sacha Urzhumtsev<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><i><span style="color:#548DD4">-----Message d'origine-----<br>
De : phenixbb-bounces@phenix-online.org [mailto:phenixbb-bounces@phenix-onl</span></i><i><span lang="EN-US" style="color:#548DD4">ine.org] De la part de Pavel Afonine<br>
<br>
</span></i><i><span lang="EN-US" style="color:#548DD4"><o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4"> Hi Fengyun,<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4"><o:p> </o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">> I am interesting in that at what completeness of the dataset, will one<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">> use the missing fobs filled map for model building confidently without<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">> too much bias included?<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4"><o:p> </o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">I'm not aware of any systematic study on this matter, although at some<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">point I reviewed the available literature.<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4"><o:p> </o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">There are numerous examples of how the data incompleteness distorts the<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">map, and literature that discusses this. Interestingly, sometimes much<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">smaller amount of systematically missing reflections, such as plane or<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">cone in reciprocal space, may have much drastic effect than a larger<o:p></o:p></span></i></p>
<p class="MsoPlainText"><i><span lang="EN-US" style="color:#548DD4">amount of randomly missing data (if you are "lucky" enough it can mask entire structural domain).<o:p></o:p></span></i></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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