Default constructor without `mpi_comm` missing in a couple of classes

[Anders Logg (Chalmers)]

Default constructor missing for TimeSeries, FooFactor::create_matrix/vector and perhaps a few others. Important for simplicity and backwards compatibility that default constructors (using mpi_comm_world() are available.

[Prof Garth Wells]

This shouldn't be changed in low-level classes, e.g. the factories. If we add it to low-level classes, it leads to bugs down the line because it doesn't force developers to think about what the appropriate communicator is.

[Anders Logg (Chalmers)]

ok, let's leave create_foo as is. Do you remember if there are other instances than TimeSeries that have been changed?

[Prof Garth Wells]

Patrick has an open pull request for XDMFFile.

If users are not (necessarily) feeling a change, then we should keep the one constructor rather than having two.

[Anders Logg (Chalmers)]

Fix issue #691: Default constructor without mpi_comm missing in a couple of classes

→ <<cset db1316248cd6>>

[Anders Logg (Chalmers)]

Removing milestone: 1.7 (automated comment)