<div dir="ltr"><div dir="ltr">On Wed, May 17, 2023 at 2:01 PM Berend van Wachem <<a href="mailto:berend.vanwachem@ovgu.de">berend.vanwachem@ovgu.de</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear Matt,<br>
<br>
I tried it, but it doesn't seem to work.<br>
Attached is a very small working example illustrating the problem.<br>
I create a DMPlexBox Mesh, periodic in the Y direction. I then scale the Y coordinates with a factor 10, and add 1.0 to it. Both <br>
DMGetCoordinatesLocal and DMGetCellCoordinatesLocal.<br>
Then I evaluate the coordinates with DMPlexGetCellCoordinates. Most of the Y coordinates are correct, but not all of them - for <br>
instance, the minimum Y coordinate is 0.0, and this should be 1.0.<br>
<br>
Am I doing something wrong?<br></blockquote><div><br></div><div>Quickly, I see that</div><div><br></div><div> a *= 10.0 + 1.0;</div><div><br></div><div>is the same as</div><div><br></div><div> a *= 11.0;</div><div><br></div><div>not multiply by 10 and add 1. I will send it back when I get everything the way I want.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Thanks and best regards,<br>
<br>
Berend.<br>
<br>
On 5/17/23 17:58, Matthew Knepley wrote:<br>
> On Wed, May 17, 2023 at 11:20 AM Berend van Wachem <<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>>> wrote:<br>
> <br>
> Dear Matt,<br>
> <br>
> Is there a way to 'redo' the DMLocalizeCoordinates() ? Or to undo it?<br>
> Alternatively, can we make the calling of DMLocalizeCoordinates() in the DMPlexCreate...() routines optional?<br>
> <br>
> Otherwise, we would have to copy all arrays of coordinates from DMGetCoordinatesLocal() and DMGetCellCoordinatesLocal() before<br>
> scaling them.<br>
> <br>
> <br>
> I am likely not being clear. I think all you have to do is the following:<br>
> <br>
> DMGetCoordinatesLocal(dm, &xl);<br>
> VecScale(xl, scale);<br>
> DMSetCoordinatesLocal(dm, xl);<br>
> DMGetCellCoordinatesLocal(dm, &xl);<br>
> VecScale(xl, scale);<br>
> DMSetCellCoordinatesLocal(dm, xl);<br>
> <br>
> Does this not work?<br>
> <br>
> Thanks,<br>
> <br>
> Matt<br>
> <br>
> Best regards, Berend.<br>
> <br>
> On 5/17/23 16:35, Matthew Knepley wrote:<br>
> > On Wed, May 17, 2023 at 10:21 AM Berend van Wachem <<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>><br>
> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>>>> wrote:<br>
> ><br>
> > Dear Matt,<br>
> ><br>
> > Thanks for getting back to me so quickly.<br>
> ><br>
> > If I scale each of the coordinates of the mesh (say, I want to cube each<br>
> > co-ordinate), and I do this for both:<br>
> ><br>
> > DMGetCoordinatesLocal();<br>
> > DMGetCellCoordinatesLocal();<br>
> ><br>
> > How do I know I am not cubing one coordinate multiple times?<br>
> ><br>
> ><br>
> > Good question. Right now, the only connection between the two sets of coordinates is DMLocalizeCoordinates(). Since<br>
> sometimes<br>
> > people want to do non-trivial things to<br>
> > coordinates, I prefer not to push in an API for "just" scaling, but I could be convinced<br>
> > the other way.<br>
> ><br>
> > Thanks,<br>
> ><br>
> > Matt<br>
> ><br>
> > Thanks, Berend.<br>
> ><br>
> > On 5/17/23 16:10, Matthew Knepley wrote:<br>
> > > On Wed, May 17, 2023 at 10:02 AM Berend van Wachem<br>
> > > <<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a><br>
> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>>> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>><br>
> > <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a> <mailto:<a href="mailto:berend.vanwachem@ovgu.de" target="_blank">berend.vanwachem@ovgu.de</a>>>>> wrote:<br>
> > ><br>
> > > Dear PETSc Team,<br>
> > ><br>
> > > We are using DMPlex, and we create a mesh using<br>
> > ><br>
> > > DMPlexCreateBoxMesh (.... );<br>
> > ><br>
> > > and get a uniform mesh. The mesh is periodic.<br>
> > ><br>
> > > We typically want to "scale" the coordinates (vertices) of the mesh,<br>
> > > and<br>
> > > to achieve this, we call<br>
> > ><br>
> > > DMGetCoordinatesLocal(dm, &coordinates);<br>
> > ><br>
> > > and scale the entries in the Vector coordinates appropriately.<br>
> > ><br>
> > > and then<br>
> > ><br>
> > > DMSetCoordinatesLocal(dm, coordinates);<br>
> > ><br>
> > ><br>
> > > After this, we localise the coordinates by calling<br>
> > ><br>
> > > DMLocalizeCoordinates(dm);<br>
> > ><br>
> > > This worked fine up to PETSc 3.18, but with versions after this, the<br>
> > > coordinates we get from the call<br>
> > ><br>
> > > DMPlexGetCellCoordinates(dm, CellID, &isDG, &CoordSize,<br>
> > > &ArrayCoordinates, &Coordinates);<br>
> > ><br>
> > > are no longer correct if the mesh is periodic. A number of the<br>
> > > coordinates returned from calling DMPlexGetCellCoordinates are wrong.<br>
> > ><br>
> > > I think, this is because DMLocalizeCoordinates is now automatically<br>
> > > called within the routine DMPlexCreateBoxMesh.<br>
> > ><br>
> > > So, my question is: How should we scale the coordinates from a periodic<br>
> > > DMPlex mesh so that they are reflected correctly when calling both<br>
> > > DMGetCoordinatesLocal and DMPlexGetCellCoordinates, with PETSc versions<br>
> > > >= 3.18?<br>
> > ><br>
> > ><br>
> > > I think we might have to add an API function. For now, when you scale<br>
> > > the coordinates,<br>
> > > can you scale both copies?<br>
> > ><br>
> > > DMGetCoordinatesLocal()<br>
> > > DMGetCellCoordinatesLocal();<br>
> > ><br>
> > > and then set them back.<br>
> > ><br>
> > > Thanks,<br>
> > ><br>
> > > Matt<br>
> > ><br>
> > > Many thanks, Berend.<br>
> > ><br>
> > > --<br>
> > > What most experimenters take for granted before they begin their<br>
> > > experiments is infinitely more interesting than any results to which<br>
> > > their experiments lead.<br>
> > > -- Norbert Wiener<br>
> > ><br>
> > > <a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a> <<a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a>><br>
> <<a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a> <<a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a>>> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a><br>
> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a>><br>
> > <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a>>>><br>
> ><br>
> ><br>
> ><br>
> > --<br>
> > What most experimenters take for granted before they begin their experiments is infinitely more interesting than any<br>
> results to<br>
> > which their experiments lead.<br>
> > -- Norbert Wiener<br>
> ><br>
> > <a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a> <<a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a>> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a><br>
> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a>>><br>
> <br>
> <br>
> <br>
> -- <br>
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to <br>
> which their experiments lead.<br>
> -- Norbert Wiener<br>
> <br>
> <a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">https://www.cse.buffalo.edu/~knepley/</a> <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank">http://www.cse.buffalo.edu/~knepley/</a>></blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>