_known_solutions->empty() must not be called otherwise there might be
PETSc errors, because not all ranks might execute the same PETSc calls.

Get constrained DOF table for all vars/components.

The integer_sequence is available since c++14.

The variable component offsets are absolute and the derived
DOF table must have all the bulk DOF table global component
offset for each variable.

If the boundary mesh is larger then the definition region
of the bulk component, then a nop is returned.
This usually indicates wrong geometry or something horrible.

DOF: partial_sum
BC: iota

The original code issues a warning: type qualifiers ignored on cast result type
since gcc-8.1. The cast is unnecessary because both
operands of the comparison are unsined ints.

Needed for PETSc to be called before acccessing the input_vector.

[NL] TimeStepping. Explicit catch bad_alloc.

When the time stepping vector is too large bad_alloc
or length_error is thrown. It is catched only in the project
data parser, too far away from the time stepper.

Dmitri Naumov authored 7 years ago and Dmitri Naumov committed 7 years ago

Especially the creation of ghost nodes.

[dt] Reduced the tolerance in the time step size calculation under the constraint of specified times

 in descending order

This also fixes the doxygen warning for undocumented
process_id parameter