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<div class="moz-cite-prefix">I added "use" flag (at the time when I
was adding all other scatterer flags) rather as a placeholder for
a future use, so yes, indeed, currently it is not respected in
fcalc and gradients calculation (though it should be respected!).
Perhaps it's time to start using it...<br>
<br>
Pavel<br>
<br>
On 4/15/13 11:58 AM, Richard Gildea wrote:<br>
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cite="mid:CACCG97E5XA=46HT6u-RL5u_xMd-q428NVpzG1tfgbQs97XbVFw@mail.gmail.com"
type="cite">
<div dir="ltr">Are the same scatterers contributing to f_calc for
every calculation, or will the scatterers that are contributing
vary from calculation to calculation? In the case of the former
it might be simplest to create a new copy of the xray_structure
with only those scatterers.
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<br>
</div>
<div>It looks the "use" flag isn't actually respected in the
structure factor or gradient calculations as far as I can
tell. If you feel you need something like this rather than
creating new copies of the xray_structure with only the
scatterers you need or alternatively setting the occupancy to
zero, then this is probably something we can add into the
code. There is some code in cctbx/xray/scatterer_flags.h
for flags_set_grad_*() that will set a selection of gradients
all at once in C++, but I don't see an equivalent for
set_use_*(). I suspect that the overhead of looping through
the scatterers to set flags in Python would be small compared
to the cost of calculating the structure factors in the first
place.</div>
<div><br>
</div>
<div>Cheers,</div>
<div><br>
</div>
<div>Richard</div>
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<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On 15 April 2013 10:40, Jan Marten
Simons <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:marten@xtal.rwth-aachen.de" target="_blank">marten@xtal.rwth-aachen.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Am Montag
15 April 2013 18:33:00 schrieb Jan Marten Simons:<br>
> Hi,<br>
><br>
> while working on a really fast way to calculate the
structure factors of a<br>
> few millions of different modifications of a structure
with only the<br>
> selected scatterers contributing to f_calc ....<br>
<br>
[...]<br>
<br>
> (I think building a larger structure and working with<br>
> selections might be faster than creating lots of
different structures<br>
> containing only the desired scatterers, but I might be
wrong on this.)<br>
<br>
I've found "flags" might be what I'm looking for. So if I
could set the "use"<br>
flag for all scatterers at once and if it was taken into
consideration during<br>
structure factor calculation then I think it would most
likely be the fastest<br>
way to enable or disable the contribution of individual
scatterers to the<br>
structure factors. Am I right on this and how would I best
interface with the<br>
flags mechanism (from python)?<br>
<br>
Cheers,<br>
<br>
Jan<br>
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