On Jan 27, 2012 12:58 AM, "Anders Logg" <l...@simula.no> wrote: > > On Wed, Jan 25, 2012 at 03:21:12PM +0100, Joachim Berdal Haga wrote: > > Hi, > > > > I'm looking a bit on assembly performance at the moment. It looks like > > a lot of time (almost 25% in poisson/linear lagrange) of the time is > > spent in these two lines of GenericFunction::evaluate(): > > > > Array<double> _values(value_size(), values); > > const Array<double> x(cell.geometric_dimension, > > const_cast<double*>(coordinates)); > > > > This seems to be because of the instantiation of boost::shared_arrays. > > The ownership of the array data is not transferred (the data will be > > deleted by the caller of evaluate()), so this does not really add any > > safety. > > > > I don't have a complete picture of how Array<> is used, does the > > Python layer rely on the shared semantics (in other places)? If not, > > it might be better to make them non-shared and create copies for use > > in Python where needed. > > Would it help if we do this: > > 1. Make GenericFunction::evaluate an inline function that just calls > a new version of GenericFunction::eval. > > 2. The new version of GenericFunction::eval has the same > implementation as the current evaluate() function. > > The result would be that we get two eval() functions, one with plain > pointers and one with Array(). A C++ user (and the JIT-compiled > expressions) would use the plain pointer version, while the Array > version gets wrapped for Python subclassing (where I assume the extra > cost will not make a difference).
I would discourage this solution as it diverge the interfaces between C++ and Python, introduce an interface change which cannot be backported and it circumvents the original problem of Array<> being costly to instantiate. Johan > -- > Anders > > > > > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : dolfin@lists.launchpad.net > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp
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