Question #103034 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/103034
Murtazo Nazarov posted a new comment: Anders Logg wrote: > Your question #103034 on DOLFIN changed: > https://answers.launchpad.net/dolfin/+question/103034 > > Anders Logg posted a new comment: > On Sun, Mar 14, 2010 at 11:48:21PM -0000, Murtazo Nazarov wrote: > >> Question #103034 on DOLFIN changed: >> https://answers.launchpad.net/dolfin/+question/103034 >> >> Murtazo Nazarov posted a new comment: >> Murtazo Nazarov wrote: >> >>> Your question #103034 on DOLFIN changed: >>> https://answers.launchpad.net/dolfin/+question/103034 >>> >>> Status: Answered => Open >>> >>> You are still having a problem: >>> Anders Logg wrote: >>> >>> >>>> Question #103034 on DOLFIN changed: >>>> https://answers.launchpad.net/dolfin/+question/103034 >>>> >>>> Status: Open => Answered >>>> >>>> Anders Logg proposed the following answer: >>>> On Wed, Mar 03, 2010 at 02:36:59AM -0000, Murtazo Nazarov wrote: >>>> >>>> >>>> >>>>> New question #103034 on DOLFIN: >>>>> https://answers.launchpad.net/dolfin/+question/103034 >>>>> >>>>> Hi, >>>>> >>>>> I am wondering how to compute an L1-norm, and L_inf norm of a functional >>>>> on the cell. For instance how to compute >>>>> >>>>> 1. ||\div(Pu)||_{L_\infty} ? >>>>> >>>>> >>>>> >>>> Try projecting div(Pu) onto piecewise constants and then pick the >>>> largest absolute value in the vector. >>>> >>>> >>>> >>>> >>> I need L_inf norm on the cell. With this way, doesn't give the L_inf for >>> the entire domain? >>> >>> murtazo >>> >>> >>> >> Instead of projecting div(Pu) onto piecewise constants, I projected it >> into dG(1), with this way I get three values on each cell, which I can >> then pick up the largest of them. That gives me then L_inf_K, where K is >> a cell. Now, I cannot figured out how is the numbering done for the >> dG(1) elements. >> >> If N is a total number of cells, then my projected vector Pdg has 3*N >> elements. How can I pick up elements of Pdg in the cell K? >> >> Thanks, >> murtazo >> > > Why do you use DG(1) instead of DG(0)? If you use DG(0), the numbering > is easier. > > DG(0) gives me an average of the function I have on the cell, however the values can be large on the vertices especially in the places where shocks exist. murtazo > -- > Anders > > > >>>>> 2. ||\div(Pu)||_{L_1} ? >>>>> >>>>> >>>>> >>>> Try >>>> >>>> M = abs(div(Pu))*dx >>>> >>>> >>>> >>>> >>>> >>>> >>>>> where u is velocity (vector) and P is pressure (scalar). L2 norm is >>>>> obvious to do. >>>>> >>>>> I use C++ interface >>>>> >>>>> >>>>> >>>>> >>> > > -- 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
