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<div>Dave,</div>
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<div>The grids all share the same processors and are kept in sync at the end of each coarse-domain timestep. So, the outer nest runs on the processors first, then that nest waits while the finer nest is calculated. Then, the fine nest waits while the coarse
nest calculates, and on-and-on it goes. So, within a timestep, each nest is run sequentially. However, if one sees thinks of this in terms of the processor usage, they are simultaneous.</div>
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<div>-Bill</div>
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<div style="font-size: 12px;"><font class="Apple-style-span" face="Helvetica"><font style="font-size: 14px;"><font size="2"><span style="font-size: 10pt;"><b><font class="Apple-style-span" color="#dc871b">___________________________________________________________________</font></b></span></font></font></font></div>
<div style="font-size: 12px;"><font class="Apple-style-span" face="Helvetica"><font color="#dc871b" size="1" style="font-family: Helvetica, sans-serif;"><b><br>
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<div style="font-size: 12px;"><font class="Apple-style-span" face="Helvetica"><font style="font-family: Helvetica, sans-serif;"><b>William I. Gustafson Jr., Ph.D.<br>
</b></font><font style="font-family: Helvetica, sans-serif;"><font style="font-size: 11px;">Scientist<br>
ATMOSPHERIC SCIENCES AND GLOBAL CHANGE DIVISION<br>
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Pacific Northwest National Laboratory<br>
P.O. 999, MSIN K9-30<br>
Richland, WA 99352<br>
Tel: 509-372-6110<br>
</font></font></font><span class="Apple-style-span" style="font-size: 11px;"><u><a href="mailto:William.Gustafson@pnnl.gov"><font color="#df8800">William.Gustafson@pnnl.gov</font></a></u></span></div>
<div style="font-size: 12px;"><font class="Apple-style-span" face="Helvetica"><font style="font-family: Helvetica, sans-serif;"><font style="font-size: 11px;"><a href="http://www.pnnl.gov/atmospheric/staff/staff_info.asp?staff_num=5716" style="color: blue;"><font class="Apple-style-span" color="#dc871b">http://www.pnnl.gov/atmospheric/staff/staff_info.asp?staff_num=5716</font></a></font></font></font></div>
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<span class="Apple-style-span" style="font-size: 12px; font-family: Helvetica, sans-serif;"><font class="Apple-style-span" style="font-size: 11px;" color="#df8800"><a href="http://www.researcherid.com/rid/A-7732-2008">http://www.researcherid.com/rid/A-7732-2008</a></font></span></div>
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<div style="font-family:Calibri; font-size:11pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt">
<span style="font-weight:bold">From: </span><<a href="mailto:wrf-users-bounces@ucar.edu">wrf-users-bounces@ucar.edu</a>> on behalf of David Smith <<a href="mailto:dsmith@uvi.edu">dsmith@uvi.edu</a>><br>
<span style="font-weight:bold">Date: </span>Wednesday, June 8, 2016 at 12:55 PM<br>
<span style="font-weight:bold">To: </span>wrf-users <<a href="mailto:wrf-users@ucar.edu">wrf-users@ucar.edu</a>><br>
<span style="font-weight:bold">Subject: </span>[Wrf-users] How wrf processes nests<br>
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<div>Hi,</div>
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<div> I am running wrf using mpirun on a 10 node cluster with 12 processors each – 120 total. I have two fine nests (0.333 km) within a 1.0 km coarser nest. I am trying to make a judicious choice for the dimensions of the fine nests, to minimize runtime.
(Making one fine nest would double the area.) Will wrf run the two fine grids sequentially or simultaneously? I would think this info would be in the users guide, but I’m not finding it. Thanks!</div>
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<div>Dave Smith</div>
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<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri">Dr. David J Smith</font></font></div>
<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri">College of Science and Mathematics</font></font></div>
<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri">University of the Virgin Islands</font></font></div>
<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri">St. Thomas, VI 00802</font></font></div>
<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri">340 693-1257</font></font></div>
<div><font class="Apple-style-span" color="rgb(0, 0, 0)"><font class="Apple-style-span" face="Calibri"><a href="mailto:dsmith@uvi.edu">dsmith@uvi.edu</a></font></font></div>
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