ufl team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, May 02, 2011 at 01:26:58PM +0200, Martin Sandve Alnæs wrote:
> Declaring default arguments with mutable object like dicts such as
> this line is dangerous in Python.
> def compute_form_data(self, object_names={}, common_cell=None,
> element_mapping={}):
> If object_names or element_mapping is modified, the
> modifications change the default object for future calls.

How do you mean modified? You mean the default will change if a value
is passed to the function with element_mapping=<something>?

> Therefore it's a good habit to use None instead:
> def compute_form_data(self, object_names=None, common_cell=None,
> element_mapping=None):
>     if object_names is None: object_names = {}
>     if element_mapping is None: element_mapping = {}
>     ...

ok.

--
Anders



> On 2 May 2011 10:13,  <noreply@xxxxxxxxxxxxx> wrote:
> > ------------------------------------------------------------
> > revno: 1021
> > committer: Anders Logg <logg@xxxxxxxxx>
> > branch nick: ufl-main
> > timestamp: Mon 2011-05-02 10:11:12 +0200
> > message:
> >  Initial work on replacement for UFL set_foo functions
> > modified:
> >  ufl/algorithms/preprocess.py
> >  ufl/form.py
> >
> >
> >
> > Your team UFL Core Team is subscribed to branch lp:ufl.
> > To unsubscribe from this branch go to https://code.launchpad.net/~ufl-core/ufl/main/+edit-subscription
> >
> > === modified file 'ufl/algorithms/preprocess.py'
> > --- ufl/algorithms/preprocess.py        2011-04-26 20:03:38 +0000
> > +++ ufl/algorithms/preprocess.py        2011-05-02 08:11:12 +0000
> > @@ -7,7 +7,7 @@
> >  __license__  = "GNU LGPL version 3 or any later version"
> >  __date__ = "2009-12-07"
> >
> > -# Last changed: 2011-04-26
> > +# Last changed: 2011-05-02
> >
> >  from ufl.log import info, debug, warning, error
> >  from ufl.assertions import ufl_assert
> > @@ -21,7 +21,7 @@
> >  from ufl.algorithms.analysis import extract_num_sub_domains, extract_integral_data, unique_tuple
> >  from ufl.algorithms.formdata import FormData
> >
> > -def preprocess(form, object_names={}, common_cell=None):
> > +def preprocess(form, object_names={}, common_cell=None, element_mapping={}):
> >     """
> >     Preprocess raw input form to obtain form metadata, including a
> >     modified (preprocessed) form more easily manipulated by form
> > @@ -94,24 +94,8 @@
> >     form_data.sub_elements        = extract_sub_elements(form_data.elements)
> >     form_data.unique_sub_elements = unique_tuple(form_data.sub_elements)
> >
> > -    # FIXME: Need to look at logic here, FFC does not support the last two cases
> > -
> > -    # Store cell
> > -    if not common_cell is None:
> > -        form_data.cell = common_cell
> > -    elif form_data.elements:
> > -        cells = [element.cell() for element in form_data.elements]
> > -        cells = [cell for cell in cells if not cell.domain() is None]
> > -        if len(cells) == 0:
> > -            error("Unable to extract form data. Reason: Missing cell definition in form.")
> > -        form_data.cell = cells[0]
> > -    elif form._integrals:
> > -        # Special case to allow functionals only depending on geometric variables, with no elements
> > -        form_data.cell = form._integrals[0].integrand().cell()
> > -    else:
> > -        # Special case to allow integral of constants to pass through without crashing
> > -        form_data.cell = None
> > -        warning("Form is empty, no elements or integrals, cell is undefined.")
> > +    # Store common cell
> > +    form_data.cell = common_cell
> >
> >     # Store data related to cell
> >     if form_data.cell is None:
> >
> > === modified file 'ufl/form.py'
> > --- ufl/form.py 2011-04-26 20:03:38 +0000
> > +++ ufl/form.py 2011-05-02 08:11:12 +0000
> > @@ -96,11 +96,11 @@
> >         "Return form metadata (None if form has not been preprocessed)"
> >         return self._form_data
> >
> > -    def compute_form_data(self, object_names={}, common_cell=None):
> > +    def compute_form_data(self, object_names={}, common_cell=None, element_mapping={}):
> >         "Compute and return form metadata"
> >         if self._form_data is None:
> >             from ufl.algorithms.preprocess import preprocess
> > -            self._form_data = preprocess(self, object_names, common_cell)
> > +            self._form_data = preprocess(self, object_names, common_cell, element_mapping)
> >         return self.form_data()
> >
> >     def is_preprocessed(self):
> >
> >
> >
>
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