<div dir="ltr">Steve<div><br></div><div>This is done mostly for historic reasons. I want to get rid of this as well. However, my approach is even more extreme.</div><div><br></div><div>Sometimes, one wants to output the RHS. In this case, the RHS variables need to be calculated in the Analysis bin. This is a bit of a waste, since MoL will then re-calculate them at the beginning of the next time step.</div><div><br></div><div>My approach is:</div><div><br></div><div>- calculate the RHS in MoL_PostStep</div><div>- do not calculate them in MoL_CalcRHS (this schedule group remains empty)</div><div>- tell MoL to not "initialize" the RHS variables with zero</div><div>- you can then simply skip the initial copy as well (unless some other routine is looking at it)</div><div><br></div><div>-erik</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Dec 8, 2016 at 11:11 AM, Steven R. Brandt <span dir="ltr"><<a href="mailto:sbrandt@cct.lsu.edu" target="_blank">sbrandt@cct.lsu.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">So I'm curious about why Cactus/MoL does things the way it does.<br>
For the sake of this example, consider that we are evolving the variable<br>
B and we compute B_RHS during the evolution.<br>
<br>
First, we fill in initial data. B = something.<br>
Second, at the start of the iteration loop, we rotate time levels. B --><br>
B_p, B --> invalid<br>
Third, MoL_InitialCopy copies the previous time level to the current.<br>
B_p --> B<br>
Fourth, we evolve. B_RHS = Foo(B)<br>
<br>
MoL_InitialCopy seems to be a wasted step. It would not be needed if<br>
(1) time levels were rotated at the end of the iteration loop, or<br>
(2) we computed B_RHS = Foo(B_p)<br>
<br>
Am I missing something? Why do we do things that way?<br>
<br>
--Steve<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br><a href="http://www.perimeterinstitute.ca/personal/eschnetter/" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a></div>
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