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<p style="margin-top:0;margin-bottom:0">Dear Sandeep,</p>
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<p style="margin-top:0;margin-bottom:0">Look for routines intp_rst, grad_rstd, etc., and calls to them</p>
<p style="margin-top:0;margin-bottom:0">in convect.f and induct.f</p>
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<p style="margin-top:0;margin-bottom:0">There are several routines that map onto the finer GL mesh </p>
<p style="margin-top:0;margin-bottom:0">from the base GLL mesh.</p>
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<p style="margin-top:0;margin-bottom:0">The metrics, J*dr/dx, J*dr/dy, etc., are already on the fine</p>
<p style="margin-top:0;margin-bottom:0">mesh and collocated with the quadrature weight on that fine</p>
<p style="margin-top:0;margin-bottom:0">mesh when they are constructed (in set_dealias_rx in induct.f).</p>
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<p style="margin-top:0;margin-bottom:0">The mathematics of these procedure is described in Sec. 3 of</p>
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<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">Stabilization of the spectral element method in convection dominated flows by recovery of skew-symmetry</span></p>
<li itemscope="" itemtype="http://schema.org/Person" class="u-mb-2 u-pt-4 u-pb-4" style="color: rgb(51, 51, 51); font-family: 'Source Sans Pro', Helvetica, Arial, sans-serif; font-size: 14px; orphans: 2; widows: 2; background-color: rgb(252, 252, 252); box-sizing: border-box; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding-right: 0px; padding-left: 0px; display: inline-block; vertical-align: middle; margin-bottom: 2px !important; padding-top: 4px !important; padding-bottom: 4px !important;">
<span itemprop="name" class="authors__name" style="box-sizing: border-box;">Johan Malm,</span><span class="author-information" style="box-sizing: border-box;"><span class="authors__contact" style="box-sizing: border-box;"> </span></span></li><li itemscope="" itemtype="http://schema.org/Person" class="u-mb-2 u-pt-4 u-pb-4" style="color: rgb(51, 51, 51); font-family: 'Source Sans Pro', Helvetica, Arial, sans-serif; font-size: 14px; orphans: 2; widows: 2; background-color: rgb(252, 252, 252); box-sizing: border-box; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding-right: 0px; padding-left: 0px; display: inline-block; vertical-align: middle; margin-bottom: 2px !important; padding-top: 4px !important; padding-bottom: 4px !important;">
<span itemprop="name" class="authors__name" style="box-sizing: border-box;">Philipp Schlatter </span></li><li itemscope="" itemtype="http://schema.org/Person" class="u-mb-2 u-pt-4 u-pb-4" style="color: rgb(51, 51, 51); font-family: 'Source Sans Pro', Helvetica, Arial, sans-serif; font-size: 14px; orphans: 2; widows: 2; background-color: rgb(252, 252, 252); box-sizing: border-box; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding-right: 0px; padding-left: 0px; display: inline-block; vertical-align: middle; margin-bottom: 2px !important; padding-top: 4px !important; padding-bottom: 4px !important;">
<span itemprop="name" class="authors__name" style="box-sizing: border-box;">Paul F. Fischer </span></li><li itemscope="" itemtype="http://schema.org/Person" class="u-mb-2 u-pt-4 u-pb-4" style="color: rgb(51, 51, 51); font-family: 'Source Sans Pro', Helvetica, Arial, sans-serif; font-size: 14px; orphans: 2; widows: 2; background-color: rgb(252, 252, 252); box-sizing: border-box; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding-right: 0px; padding-left: 0px; display: inline-block; vertical-align: middle; margin-bottom: 2px !important; padding-top: 4px !important; padding-bottom: 4px !important;">
<span itemprop="name" class="authors__name" style="box-sizing: border-box;">Dan S. Henningson</span>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> </span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">NOTE: After you create your nonlinear source term, you</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">should divide the value each point x_{ijke} by bm1(i,j,k,e),</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">because Nek multiplies the entry in qvol by bm1(i,j,k,e).</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">In your case, however, you've already accounted for the mass</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">matrix by incorporated the mass matrix on the fine-GL points.</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">I would set up your u x nabla term via a call to userchk</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">and store the result (already divided by bm1), then just</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">dereference it inside qvol. via:</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> subroutine qvol(i,j,k,eg)</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> ...</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> ...</span></p>
<p><font face="CMBX12"><span style="font-size: 13pt;"> common /mynonlin/ s(lx1,ly1,lz1,lelt,ldim)</span></font></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> integer e,eg</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> e=gllel(eg)</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> qvol=s(i,j,k,e,ifield-2)</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> return</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"> end</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">or something like that.</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">The </span><font face="CMBX12"><span style="font-size: 17px;">time step will all be correct and you will get 2nd or</span></font></p>
<p><font face="CMBX12"><span style="font-size: 17px;">3rd-order accuracy in time via Nek's standard BDFk/EXTk</span></font></p>
<p><font face="CMBX12"><span style="font-size: 17px;"><br>
</span></font></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">hth,</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'">Paul</span></p>
<p><span style="font-size: 13.000000pt; font-family: 'CMBX12'"><br>
</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Nek5000-users <nek5000-users-bounces@lists.mcs.anl.gov> on behalf of nek5000-users@lists.mcs.anl.gov <nek5000-users@lists.mcs.anl.gov><br>
<b>Sent:</b> Wednesday, May 23, 2018 4:50:19 AM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> [Nek5000-users] dealias; mass matrix; interp_rstd</font>
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<div class="x_gmail_default" style="font-size:small">Dear Neks,</div>
<div class="x_gmail_default" style="font-size:small">I solve</div>
<div class="x_gmail_default" style="font-size:small">\partial A/\partial t = \nabla^2 A + u x Curl A,</div>
<div class="x_gmail_default" style="font-size:small">where A = (s1,s2,s3) </div>
<div class="x_gmail_default" style="font-size:small">I solve three scalar equations with respective components of u x Curl A as forcing terms in qvol.</div>
<div class="x_gmail_default" style="font-size:small">I would like to compute the dealiased product of u x Curl A</div>
<div class="x_gmail_default" style="font-size:small">I build my code based on kov_stokes_test.usr and subroutines in induct.f</div>
<div class="x_gmail_default" style="font-size:small">I compute local curl, project curl and U onto fine mesh, perform product and project the product back to coarse mesh using interp_rstd<br>
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<div class="x_gmail_default" style="color:rgb(34,34,34); font-family:arial,sans-serif; font-size:small; font-style:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px">
However, I am not sure about the multiplication of mass matrices for the product in these subroutines.<br>
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<div class="x_gmail_default" style="font-size:small">I attach my usr, rea and SIZE files.</div>
<div class="x_gmail_default" style="font-size:small">Your suggestions are welcome.</div>
<div class="x_gmail_default" style="font-size:small">Thanks,</div>
<div class="x_gmail_default" style="font-size:small">Sandeep</div>
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