- firedrake - imperial.ac.uk

Prescribe pressure at a corner for Darcy's equation
by Justin Chang 13 Feb '17

13 Feb '17

Hi all, I am trying to simulate the 2D benchmark Elder problem, which is density-driven fluid flow in porous media. The problem is essentially Darcy's equation where no flow boundary conditions are enforced on all four sides (let's suppose the computational domain is 600m by 150m). To ensure uniqueness, pressure is prescribed at the top left and top right corners. Suppose I want to use the RT0 formulation. If my pressure is non-zero, how would I prescribe if I were to use one of the built-in Mesh functions (as opposed to GMSH)? I know for RT0, the pressure bc is prescribed weakly but how do I literally only have the two element faces that connect each of the top left and top right corners apply said boundary condition? Thanks, Justin

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Firedrake users and developers meeting dealines FRIDAY.
by David Ham 09 Feb '17

09 Feb '17

Hi All, Just a little poke to remind you that the abstract and early registration deadline for Firedrake '17 is this Friday. Links for both are available via the workshop page: http://firedrakeproject.org/firedrake_17.html Regards, David -- Dr David Ham Department of Mathematics Imperial College London

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Re: [firedrake] Firedrake user and developer workshop -- 27 & 28 March 2017
by David Ham 07 Feb '17

07 Feb '17

Hi All, Sorry, I hadn't realised I'd spammed the whole list with that mail! The simple answer is that Imperial is in a very touristy area so there are tonnes of hotels. Just typing Imperial College London into, for example, expedia turns up very many within a short walk. This is, unfortunately, a very expensive area but we hope you'll appreciate our effort to make your trip more affordable by devaluing the pound by 20% ;). Justin: the hotel Matt pointed you to is also, I'm sure, just fine. It's on the other side of the park so it's a little further away, but you get a nice walk across Kensington Gardens. Regards, David On Tue, 7 Feb 2017 at 16:59 Julian Andrej <juan(a)tf.uni-kiel.de> wrote: > I don't know if its recommended but i at the Best Western Hebron, > which is 15minutes from the location and reasonably priced. > > On Tue, Feb 7, 2017 at 5:29 PM, Justin Chang <jychang48(a)gmail.com> wrote: > > I am also wondering the same thing regarding where to stay. Knepley > tells me > > Hilton Hyde Park is one place. Is that recommended? > > > > On Tue, Feb 7, 2017 at 10:24 AM Francis Poulin <fpoulin(a)uwaterloo.ca> > wrote: > >> > >> Hello, > >> > >> Yes, I still am. I even have an abstract that I plan to submit later > >> today. Sorry for my tardiness. I will probably submit it this evening > my > >> time. > >> > >> Does anyone have any advice as to where would be convenient to stay? > It's > >> been a decade since I've been to London and sadly have never visited > >> Imperial. I am looking forward to it. > >> > >> > >> Cheers, Francis > >> > >> > >> ------------------ > >> Francis Poulin > >> Associate Professor > >> Department of Applied Mathematics > >> University of Waterloo > >> > >> email: fpoulin(a)uwaterloo.ca > >> Web: https://uwaterloo.ca/poulin-research-group/ > >> Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > >> > >> From: firedrake-bounces(a)imperial.ac.uk [ > firedrake-bounces(a)imperial.ac.uk] > >> on behalf of David Ham [David.Ham(a)imperial.ac.uk] > >> Sent: Tuesday, February 07, 2017 4:36 AM > >> To: firedrake > >> Subject: Re: [firedrake] Firedrake user and developer workshop -- 27 & > 28 > >> March 2017 > >> > >> Hi Francis, > >> > >> Thanks for your ongoing support for Firedrake. I was wondering if you > were > >> still thinking of coming to Firedrake '17. > >> > >> Regards, > >> > >> David > >> > >> On Tue, 15 Nov 2016 at 15:41 Francis Poulin <fpoulin(a)uwaterloo.ca> > wrote: > >>> > >>> Hello David, > >>> > >>> This sounds great! I will most certainly try to attend and hopefully > >>> bring a grad student along. > >>> > >>> I am also happy to help if I can and look forward to meeting everyone > in > >>> person. > >>> > >>> Cheers, Francis > >>> > >>> > >>> > >>> ------------------ > >>> Francis Poulin > >>> Associate Professor > >>> Department of Applied Mathematics > >>> University of Waterloo > >>> > >>> email: fpoulin(a)uwaterloo.ca > >>> Web: https://uwaterloo.ca/poulin-research-group/ > >>> Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > >>> > >>> ________________________________ > >>> From: firedrake-bounces(a)imperial.ac.uk [ > firedrake-bounces(a)imperial.ac.uk] > >>> on behalf of David Ham [David.Ham(a)imperial.ac.uk] > >>> Sent: Tuesday, November 15, 2016 5:59 AM > >>> To: firedrake > >>> Subject: [firedrake] Firedrake user and developer workshop -- 27 & 28 > >>> March 2017 > >>> > >>> Dear Firedrakers, > >>> > >>> The first Firedrake user and developer workshop will be held on 27 & 28 > >>> March 2017 at Imperial College London. Please save the dates! > >>> > >>> The Firedrake workshop will provide the opportunity for Firedrake users > >>> and developers to engage with each other to communicate the ways that > >>> Firedrake can be used in simulation science, the latest developments > in the > >>> project, and the future developments anticipated. The workshop will > >>> incorporate a half day Firedrake tutorial for interested new users, > and will > >>> present more experienced users with the opportunity to spend face to > face > >>> time with developers and other users. > >>> > >>> A call for contributions and registration information will be published > >>> in a few weeks. I hope to see many of you there. > >>> > >>> Regards, > >>> > >>> David > >> > >> -- > >> Dr David Ham > >> Department of Mathematics > >> Imperial College London > >> _______________________________________________ > >> firedrake mailing list > >> firedrake(a)imperial.ac.uk > >> https://mailman.ic.ac.uk/mailman/listinfo/firedrake > > > > > > _______________________________________________ > > firedrake mailing list > > firedrake(a)imperial.ac.uk > > https://mailman.ic.ac.uk/mailman/listinfo/firedrake > > > > _______________________________________________ > firedrake mailing list > firedrake(a)imperial.ac.uk > https://mailman.ic.ac.uk/mailman/listinfo/firedrake > -- Dr David Ham Department of Mathematics Imperial College London

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Re: [firedrake] Firedrake user and developer workshop -- 27 & 28 March 2017
by David Ham 07 Feb '17

07 Feb '17

Hi Francis, Thanks for your ongoing support for Firedrake. I was wondering if you were still thinking of coming to Firedrake '17. Regards, David On Tue, 15 Nov 2016 at 15:41 Francis Poulin <fpoulin(a)uwaterloo.ca> wrote: > Hello David, > > This sounds great! I will most certainly try to attend and hopefully > bring a grad student along. > > I am also happy to help if I can and look forward to meeting everyone in > person. > > Cheers, Francis > > > > ------------------ > Francis Poulin > Associate Professor > Department of Applied Mathematics > University of Waterloo > > email: fpoulin(a)uwaterloo.ca > Web: https://uwaterloo.ca/poulin-research-group/ > Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > > ------------------------------ > *From:* firedrake-bounces(a)imperial.ac.uk [firedrake-bounces(a)imperial.ac.uk] > on behalf of David Ham [David.Ham(a)imperial.ac.uk] > *Sent:* Tuesday, November 15, 2016 5:59 AM > *To:* firedrake > *Subject:* [firedrake] Firedrake user and developer workshop -- 27 & 28 > March 2017 > > Dear Firedrakers, > > The first Firedrake user and developer workshop will be held on 27 & 28 > March 2017 at Imperial College London. Please save the dates! > > The Firedrake workshop will provide the opportunity for Firedrake users > and developers to engage with each other to communicate the ways that > Firedrake can be used in simulation science, the latest developments in the > project, and the future developments anticipated. The workshop will > incorporate a half day Firedrake tutorial for interested new users, and > will present more experienced users with the opportunity to spend face to > face time with developers and other users. > > A call for contributions and registration information will be published in > a few weeks. I hope to see many of you there. > > Regards, > > David > -- Dr David Ham Department of Mathematics Imperial College London

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Re: [firedrake] Firedrake and xcode
by David Ham 07 Feb '17

07 Feb '17

Hi Francis, If you are able to give this a try this would be great. We don't currently have a clean Mac lying around to try this on. Regards, David On Thu, 2 Feb 2017 at 16:06 Francis Poulin <fpoulin(a)uwaterloo.ca> wrote: > Hello David, > > Thanks for looking into this detail. Is this something that you might > want me to try and see if the installation works? > > Cheers, Francis > > > > ------------------ > Francis Poulin > Associate Professor > Department of Applied Mathematics > University of Waterloo > > email: fpoulin(a)uwaterloo.ca > Web: https://uwaterloo.ca/poulin-research-group/ > Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > > ------------------------------ > *From:* firedrake-bounces(a)imperial.ac.uk [firedrake-bounces(a)imperial.ac.uk] > on behalf of David Ham [David.Ham(a)imperial.ac.uk] > *Sent:* Wednesday, February 01, 2017 5:28 AM > *To:* firedrake > *Subject:* Re: [firedrake] Firedrake and xcode > > Hi Francis, > > We're basically installing xcode in order to have the compilers. I wasn't > aware until this week that you could get the compilers by just installing > the much smaller xcode command line tools. It's entirely possible that this > is sufficient, but we (or someone) would need to test this. I think one > just needs to comment out lines 955 to 958 of firedrake-install and then > try running it on a clean Mac. > > Regards, > > David > > On Tue, 31 Jan 2017 at 16:42 Francis Poulin <fpoulin(a)uwaterloo.ca> wrote: > > Hello, > > I have had several students install Firedrake on a MacMini and each time > the full version of Xcode needed to be installed. Is this necessarily the > case? If yes, what in particular is needed? > > Francis > > > > ------------------ > Francis Poulin > Associate Professor > Department of Applied Mathematics > University of Waterloo > > email: fpoulin(a)uwaterloo.ca > Web: https://uwaterloo.ca/poulin-research-group/ > Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > > -- > Dr David Ham > Department of Mathematics > Imperial College London > -- Dr David Ham Department of Mathematics Imperial College London

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High-contrast Stokes problem
by Loic Gouarin 06 Feb '17

06 Feb '17

Hi, I would like to solve a Stokes problem with a viscosity which is not constant and could be high in some parts of the domain (as in sinker problem). The solvers that I want to use are in this article: http://dx.doi.org.ezproxy.math.cnrs.fr/10.1016/j.cam.2013.10.016 I would like to use a P0 interpolation for the viscosity function. Could you tell me how can I set this function into my variational formulation ? The other question is to construct the S matrix when you use the Schur complement as a preconditioner. I have to set the pressure mass matrix for S and scale it with the inverse of the viscosity. How can I do that ? Thanks, Loic -- Tel: 01 69 15 60 14 http://www.math.u-psud.fr/~gouarin https://github.com/gouarin

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Re: [firedrake] Firedrake and xcode
by David Ham 02 Feb '17

02 Feb '17

Hi Francis, We're basically installing xcode in order to have the compilers. I wasn't aware until this week that you could get the compilers by just installing the much smaller xcode command line tools. It's entirely possible that this is sufficient, but we (or someone) would need to test this. I think one just needs to comment out lines 955 to 958 of firedrake-install and then try running it on a clean Mac. Regards, David On Tue, 31 Jan 2017 at 16:42 Francis Poulin <fpoulin(a)uwaterloo.ca> wrote: > Hello, > > I have had several students install Firedrake on a MacMini and each time > the full version of Xcode needed to be installed. Is this necessarily the > case? If yes, what in particular is needed? > > Francis > > > > ------------------ > Francis Poulin > Associate Professor > Department of Applied Mathematics > University of Waterloo > > email: fpoulin(a)uwaterloo.ca > Web: https://uwaterloo.ca/poulin-research-group/ > Telephone: +1 519 888 4567 x32637 <(519)%20888-4567> > > -- Dr David Ham Department of Mathematics Imperial College London

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Firedrake and xcode
by Francis Poulin 31 Jan '17

31 Jan '17

Hello, I have had several students install Firedrake on a MacMini and each time the full version of Xcode needed to be installed. Is this necessarily the case? If yes, what in particular is needed? Francis ------------------ Francis Poulin Associate Professor Department of Applied Mathematics University of Waterloo email: fpoulin(a)uwaterloo.ca Web: https://uwaterloo.ca/poulin-research-group/ Telephone: +1 519 888 4567 x32637

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Re: [firedrake] Parallel issues and projection issues
by David Ham 27 Jan '17

27 Jan '17

Hi Will, I'll have a quick look at the parallel issue - I suspect it's just solver tolerances. Can you please provide a maths write-up of the variational problem you are solving so we can think more easily about number 2? Regards, David On Fri, 20 Jan 2017 at 13:09 William Booker <scwb(a)leeds.ac.uk> wrote: > Dear Firedrakers, > > Attached is a code for a skew symmetric FEM scheme, that should conserve > the discrete energy of the system. > > I have two issues: > > 1) When I run the code in serial, it conserves energy as expected but when > I run it in parallel there seems to be an error. Attached a graph of energy > drifts from running on 1/2 cores. > > 2) To make the code skew symmetric, I have to project physical variables ( > density, velocity) into their variational derivatives. Currently this is > done by extending the system from (vel, dens) to (vel, dens, vel_deriv, > den_deriv) and I include the projection as part of the mixed system. > Obviously this is rather expensive as I double the amount of variables > used, and I'm looking to use this for more complicated systems. > > I believe Colin mentioned to Onno, there may be a better way of including > this projection step without extending the mixed system. > > > Thanks > Will > -- Dr David Ham Department of Mathematics Imperial College London

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Re: [firedrake] Firedrake update
by David Ham 24 Jan '17

24 Jan '17

Hi David, It looks to me as if you have managed to somehow alter the permissions of your Firedrake git repository. For example this might have happened if you made the mistake of running firedrake-update under sudo. If you understand how Unix permissions work, you can change the permissions or ownership back to the correct ones for your user and all should be well. Otherwise it might be easier to just reinstall Firedrake. Regards. David On Tue, 24 Jan 2017 at 15:37 Angwenyi David <kipkoej(a)gmail.com> wrote: > Hi Firedrakers, > > I am trying to update firedrake on mac. The following error turns out. > > error: cannot open .git/FETCH_HEAD: Permission denied > > Traceback (most recent call last): > File "/Users/master/firedrake/bin/firedrake-update", line 957, in > <module> > git_update("firedrake") > File "/Users/master/firedrake/bin/firedrake-update", line 381, in > git_update > check_call(["git", "pull"]) > File "/Users/master/firedrake/bin/firedrake-update", line 228, in > check_call > subprocess.check_call(arguments, env=env) > File > "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", > line 540, in check_call > raise CalledProcessError(retcode, cmd) > subprocess.CalledProcessError: Command '['git', 'pull']' returned non-zero > exit status 1 > > > How can I resolve it? > > Thanks in advance. > > Angwenyi > -- Dr David Ham Department of Mathematics Imperial College London

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