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<p>Dear all,</p>
<p>we had in the meantime a detailed look in the matter from our
side and suspect know a problem with the OFF-file<br>
</p>
<p>If we use a mono planar version of the optic (see example in the
attachment) we can increase the nested levels ad lib.<br>
We are only limited by the fact that the spacing between the
levels is becoming so small, that it makes no sense to continue.</p>
<p>A major difference between the single and double planar optic is
that the double planar OFF-File has surfaces that intersect each
other. <br>
</p>
<p>I don't know if this is "allowed" or if it can cause McStas to
have problems during the simulation.<br>
Until a certain level of complexity it worked fine.<br>
</p>
<p>What we are currently doing is to change the function (written in
python), that generates the double planar OFF-file to generate
additional vertexes and faces at the intersection of the surfaces.
So we end up having a cleanly defined optic with no 'undefined
intersections'.<br>
<br>
I will report the outcome of this changes.</p>
<p>Best,</p>
<p>Richard<br>
</p>
<p><br>
</p>
<p> <br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 02/07/2021 09:35, Erik B Knudsen
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:f5ac62ac-4d7e-9ee6-b1b4-ef424176d0ca@fysik.dtu.dk">Dear
Richard,
<br>
Thank you for the thorough and detailed report. We will take a
look at your problem asap and report back.
<br>
cheers
<br>
Erik
<br>
<br>
On 29/06/2021 18:31, Richard Wagner wrote:
<br>
<blockquote type="cite">Dear McStas experts,
<br>
<br>
We are currently doing simulations with nested elliptical optics
and so far things ran quiet smoothly.
<br>
<br>
We generate the OFF file for the optic ourselves and use the
Guide_anyshape component.
<br>
<br>
We start with an outer layer and continue to add inner layers
one at a time.
<br>
If we then get to optical components that have a high number of
levels we run into the problem, that McStas crashes resp. aborts
the simulation.
<br>
<br>
Output in that case reads:
<br>
<br>
# McStas 2.7 - Nov. 27, 2020: [pid 64818] Signal 11 detected
SIGSEGV (Mem Error)
<br>
# Simulation: NNb (NNb.instr)
<br>
# Breakpoint: psd_monitor (Trace) 2.46 % ( 24574.0/ 1000000.0)
<br>
# Date: Tue Jun 29 17:44:13 2021
<br>
# Started: Tue Jun 29 17:44:13 2021
<br>
# Last I/O Error: No such file or directory
<br>
# McStas 2.7 - Nov. 27, 2020: Simulation stop (abort).
<br>
<br>
Or
<br>
<br>
# McStas 2.7 - Nov. 27, 2020: [pid 66573] Signal 10 detected
[proc 0] SIGBUS (Bus error)
<br>
# Simulation: NNb (NNb.instr)
<br>
# Breakpoint: nested (Trace) 85.56 % ( 855555.0/ 1000000.0)
<br>
# Date: Tue Jun 29 18:00:32 2021
<br>
# Started: Tue Jun 29 18:00:28 2021
<br>
# Last I/O Error: No such file or directory
<br>
<br>
There are many messages such as the following in the Mcstas
Window, too:
<br>
<br>
Guide_anyshape: nested: Warning: Reflectivity R=7.02318 > 1
lowered to R=1.
<br>
Guide_anyshape: nested: Warning: Reflectivity R=7.02365 > 1
lowered to R=1.
<br>
Guide_anyshape: nested: Warning: Reflectivity R=7.02412 > 1
lowered to R=1.
<br>
Guide_anyshape: nested: Warning: Reflectivity R=7.0246 > 1
lowered to R=1.
<br>
<br>
I put an example of an instrument file (+OFF , +Source
Component) of a failed run for a 1m optic in the attachment.
<br>
<br>
The trace run for instrument visualization works.
<br>
We only run into the problem for short optics <=2 m, were a
high number of nested levels is needed to completely cover the
cross section.
<br>
<br>
We run into the problem on Ubuntu 18.04 and MacOs Big Sur
machines.
<br>
<br>
Any ideas what's the problem? Are the spacing of the elliptical
getting to narrow, perhaps?
<br>
<br>
Thanks in advance,
<br>
<br>
Richard
<br>
<br>
<br>
-- <br>
*Richard Wagner*
<br>
Research Engineer
<br>
Nuclear and Particle Physics Group
<br>
Institut Laue-Langevin - ILL
<br>
71, avenue des Martyrs
<br>
CS 20156
<br>
38042 Grenoble Cedex 9
<br>
France
<br>
<br>
<a class="moz-txt-link-abbreviated" href="http://www.ill.eu">www.ill.eu</a> <<a class="moz-txt-link-abbreviated" href="http://www.ill.eu">www.ill.eu</a>>
<br>
<br>
<br>
<br>
_______________________________________________
<br>
mcstas-users mailing list
<br>
<a class="moz-txt-link-abbreviated" href="mailto:mcstas-users@mcstas.org">mcstas-users@mcstas.org</a>
<br>
<a class="moz-txt-link-freetext" href="https://mailman2.mcstas.org/mailman/listinfo/mcstas-users">https://mailman2.mcstas.org/mailman/listinfo/mcstas-users</a>
<br>
<br>
</blockquote>
<br>
</blockquote>
<div class="moz-signature">-- <br>
<b>Richard Wagner</b><br>
Research Engineer<br>
Nuclear and Particle Physics Group<br>
Institut Laue-Langevin - ILL<br>
71, avenue des Martyrs<br>
CS 20156<br>
38042 Grenoble Cedex 9<br>
France <br>
<br>
<a href="www.ill.eu"><font color="#3984c6">www.ill.eu</font></a>
<p><br>
</p>
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