Also... more generally you can construct a TypeVector object and fill it up with data... these will correctly dot with any of the FE vectors.
Derek On Dec 4, 2008, at 12:32 PM, John Peterson wrote: > On Thu, Dec 4, 2008 at 12:39 PM, bkraczek <[EMAIL PROTECTED]> > wrote: >> I'm new to libmesh, and I am not a great C++ programmer, so the >> answer to >> this may seem obvious. I am working from example 3 to implement a >> poisson >> solver with a RHS that includes the dot product of the weighting >> function >> with a vector that I set. >> >> So, working from line 351 of ex3.C, >> >> Fe(i) += JxW[qp]*fxy*phi[i][qp]; >> >> I want to change this to >> >> Fe(i) += JxW[qp]*dphi[i][qp]* gradGat ; >> >> where gradGat is the vector I desire to take the inner product >> with. How do >> I properly construct gradGat so I can get the desired dot product? > > You can construct a Gradient object like this: > > Gradient gradGat(xvalue, yvalue, zvalue); > > See: include/numerics/vector_value.h, Gradient is nothing but a > typedef for VectorValue<Number>, so you can use any of the VectorValue > constructors which are available. Also, you may want to put > parentheses, like so: > > JxW[qp]*(dphi[i][qp]* gradGat) ; > > to guarantee order of operation, but it should work either way. > > -- > John > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's > challenge > Build the coolest Linux based applications with Moblin SDK & win > great prizes > Grand prize is a trip for two to an Open Source event anywhere in > the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
