Question #152914 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/152914
Kristian B. Ølgaard posted a new comment: On 15 April 2011 13:15, Martin Sandve Alnæs <[email protected]> wrote: > Question #152914 on DOLFIN changed: > https://answers.launchpad.net/dolfin/+question/152914 > > Martin Sandve Alnæs posted a new comment: > Kristian, can you check if this seems right? Is det(f) == f for scalar f > useful? It looks right, I've never used det(f), but why not leave it in there for completeness? Kristian > In [3]: V = FiniteElement("CG", interval, 1) > > In [4]: f = Coefficient(V) > > In [5]: grad(f) > Out[5]: SpatialDerivative(Coefficient(FiniteElement('Lagrange', > Cell('interval', 1, Space(1)), 1), 0), MultiIndex((FixedIndex(0),), {0: 1})) > > In [6]: grad(f) == f.dx(0) > Out[6]: True > > In [7]: div(f) == f.dx(0) > Out[7]: True > > In [10]: inner(f,f) == f*f > Out[10]: True > > In [11]: dot(f,f) == f*f > Out[11]: True > > In [13]: det(f) == f > Out[13]: True > > Martin > > > On 15 April 2011 12:30, Kristian Ølgaard <[email protected]> wrote: > >> On 15 April 2011 10:53, Martin Sandve Alnæs <[email protected]> wrote: >> > Change grad(T) to T.dx(0), i.e. derivative in a single direction. >> > Maybe we should make grad work like .dx(0) in 1D. >> >> I think that would be a good idea. >> When testing stuff in 1D (which is intended for 2D and 3D) I find it >> annoying to change back and forth between grad() and .dx(0). >> >> Kristian >> >> > Martin >> > >> > On 15 April 2011 10:46, Bento <[email protected]> >> wrote: >> >> >> >> New question #152914 on DOLFIN: >> >> https://answers.launchpad.net/dolfin/+question/152914 >> >> >> >> Hi, >> >> >> >> I want to solve a PDE on a one-dimensional domain. The equation involves >> a >> >> first derivative. How do I express this in 1D? Here is (basically) my >> >> equation: >> >> >> >> dT/dx + d^2T/dx^2 = 0 >> >> >> >> and weak form >> >> >> >> a = (grad(T)*v - inner(grad(T), grad(v)))*dx >> >> >> >> with testfunction v and trialfunction T. When I use grad(T), I get a >> >> "shape mismatch in sum" error. The mesh is Interval(100, 0, 10) >> >> >> >> -- >> >> You received this question notification because you are a member of >> >> DOLFIN Team, which is an answer contact for DOLFIN. >> >> >> >> _______________________________________________ >> >> Mailing list: https://launchpad.net/~dolfin >> >> Post to : [email protected] >> >> Unsubscribe : https://launchpad.net/~dolfin >> >> More help : https://help.launchpad.net/ListHelp >> > >> > >> > _______________________________________________ >> > Mailing list: https://launchpad.net/~dolfin >> > Post to : [email protected] >> > Unsubscribe : https://launchpad.net/~dolfin >> > More help : https://help.launchpad.net/ListHelp >> > >> > >> > > -- > You received this question notification because you are a member of > DOLFIN Team, which is an answer contact for DOLFIN. > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp > -- You received this question notification because you are a member of DOLFIN Team, which is an answer contact for DOLFIN. _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
