Yes and yes. The dx() notation is just to be more explicit and distinguish it from the old dx=dx(0) notation. I might add an optional warning for uses like f*dx+g*dx(1), which could be forms intending dx(0) or dx().
Martin On 30 January 2013 12:15, Anders Logg <[email protected]> wrote: > On Wed, Jan 30, 2013 at 09:54:39AM +0100, Martin Sandve Alnæs wrote: > > In addition to integration over the entire domain, explained in > another > > post, we have introduced a concept called 'regions' in ufl. For this > > post, assume a single mesh. Support for multiple meshes will get some > > attention in the future. > > The ufl language changes for expressing domain relations is work in > > progress, but some useful features are already possible in trunk. We > > keep the concept of disjoint numbered subdomains, which can be easily > > represented as a single meshfunction in dolfin, having a single > integer > > label for each cell. In addition we introduce the concept of a region, > > which is the union of any number of subdomains. Thus regions of one > > domain can be overlapping by including some of the same subdomain(s). > > With some automatic symbolic manipulation in ufl, we can now express > > integrals over overlapping regions with zero additional cost at > > assembly time. > > Nice! > > > Here's the currently simplest syntax for integrals over regions: > > # Define regions as tuples of subdomain labels > > DL, DM, DR = (1,2), (2,), (2,3) # *** > > I guess 'DM = 2' will also work fine here? It will be passed to dx(DM) > so that will result in an integral over subdomain 2. > > > # Define new measures associated with the interior domains > > dx = Measure("dx")[domains] > > # Make forms for equation > > a = u*v*dx() + alpha*dot(grad(u), grad(v))*dx() # Integrals over > entire > > domain > > Is the '()' necessary here in 'dx()'? Will it work with just dx? > > -- > Anders > > > > L = f*v*dx(DR) + g*v*dx(DL) - (f+g)/2*v*dx(DM) # Integrals over > regions > > For the full running code, see this demo in the latest dolfin: > > > > > demo/undocumented/overlapping-regions/python/demo_overlapping-regions.p > > y > > Martin > > > _______________________________________________ > > Mailing list: https://launchpad.net/~fenics > > Post to : [email protected] > > Unsubscribe : https://launchpad.net/~fenics > > More help : https://help.launchpad.net/ListHelp > >
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