IMO this is pretty cool because it allows to transparantly calculate
higher order derivatives. for example this enables to implement the
linearization stage of higher-order non-linear solvers without much
additional effort compared to just evaluating the function in
question. (essentially, such higher order non-linear solvers are based
on truncating the Taylor series not after the first term -- like for the
Newton scheme -- but later. That said, they require to solve linear
systems of equations which involve tensors of orders greater than 2,
so they are not really practical as far as I can see.)
A more practical motivation for this is to allow the constraint
solvers to be used in "nested mode", i.e., linearizing the system of
equations they need to solve using automatic differentiation, but
allowing the value objects which are passed to the constraint solvers
be function evaluations themselves. (E.g. the result of a flash
calculation can also include the derivatives with regard to the
primary variables of the flow model. Note that the individual
constraint solvers need to some patches to make this work.)
this patch removes the in-file lists in favor of a global list of in
the COPYING file. this is done because (a) maintaining a list of
authors at the beginning of each source file is a major pain in the
a**, (b) for this reason, the list of authors was not accurate in
about 85% of all cases where more than one person was involved and (c)
this list is not legally binding in any way (the copyright is at the
person who authored a given change; if these lists had any legal
relevance, one could "aquire" the copyright of the module by forking
it and replacing the lists...)
most of these people like to inflict pain on themselfs (i.e., warnings
in their own code), but they usually don't like if pain is inflicted
on them by others (i.e., warnings produced by external code which they
use). This patch should make these kinds of people happy. I'm not
really sure if the code is easier to understand with this, but at
least clang does not complain for most of the warnings of
"-Weverything" anymore.
they used to be in opm-core, but this allows to be more flexible with
the dependency order: What's now called "opm-core" can easily depend
on opm-material which might come in handy for the refactoring.
Besides moving in classes from opm-core, the infrastructural code
which was still in opm-material is moved to the directory
opm/material/common. The intention is to collect these classes at a
central location to make it easy to move them to a real "core" module.
(if this is ever going to happen.)
because these classes should not have any side effects. case in point:
the warnings intended to be printed once get printed once per process
which can be quite a few times for parallel simulations with thousands
of cores. This could also be avoided by checking the MPI rank, but
IMHO this is way too much boilerplate code for a feature of questionable
value.
this lead to a compiler warning on gcc 4.8 that this case was already
covered by catching std::exception. Since we did the same in both
branches anyway, these statements were not required...
