fenics team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

Very nice.

--
Anders


On Wed, Jan 30, 2013 at 01:41:00PM +0100, Martin Sandve Alnæs wrote:
>    A note to developers on this: You can no longer use
>    ufc::form::num_cell_domains() etc to check if a form has integrals of
>    that type. Instead use ufc::form::has_cell_integrals(). See the
>    assemblers for how to use these, and the UFC.cpp file. I've added some
>    inline helper functions to UFC.h, get_cell_integral(domain), which
>    handle proper fallback to default and removes some boilerplate code
>    from the assemblers.
>    Martin
>
>    On 30 January 2013 12:32, Anders Logg <[1]logg@xxxxxxxxx> wrote:
>
>      ok.
>
>    On Wed, Jan 30, 2013 at 12:31:25PM +0100, Martin Sandve Alnæs wrote:
>    >    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 <[1][2]logg@xxxxxxxxx>
>    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?
>    >
>
>    >    >    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
>    >
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