there seems to be only a *very* limited amount of interest, the code
of the model is quite complex and there are currently no suitable
discretizations for free-flow equations in eWoms (i.e., the model
tends to be very unstable and oscillates a lot). Combined, all of this
makes maintaining this model a pain in the back, so let's remove it
some interest in these kinds of problems surfaces and until
appropriate discretizations -- like staggered grid methods -- are
available.
This works by having a "focus degree of freedom" during
linearization. When evaluating the local residual, all derivatives of
the residual/fluxes are with regard to the primary variables of that
DOF.
The two main offenders were the Forchheimer velocity model and the
model for the Stokes equations. To ensure that they continue to work,
the "powerinjection" and the "stokestest2c" problems are now both
compiled and tested with both, automatic differentiation and finite
differences, and the results of these tests is compared against the
same reference solution.
The majority of the time required to develop this patch was actually
required for testing: All tests compile and pass with debugging and
aggressive optimization flags with at least GCC 5, GCC 7 and clang
3.8, as well as Dune 2.3 and 2.4. Also, the results of flow_ebos stay
identical for Norne whilst the performance difference is below the
measurement noise on my machine. (the version with this patch applied
was actually about 1% faster.)
this belongs to the `tests/data` directory, not into the toplevel
`data` directory. Also, the input ART file for this has been renamed
to `fracture-raw.art` to avoid race conditions.
for the vertex-centered finite volume discretization, the relevant
position for calculating the gradient is *not* the position of the
center of the *sub*-control volume, but the center of the whole
control volume.
Since this patch changes the gradients of all VCFV simulations that
use twopoint gradients, quite a few new reference solutions are
required by this PR. I've looked at all of them manually and made sure
that they look reasonable. (The PR also includes a new reference
solution for the test for the adaptive finger problem -- which uses
ECFV -- but that's because the grid refinement seems to be quite
sensitive to the solution proceedure for that problem, not because
there's any difference in the solutions that can be noticed visually.)
note that all simulations that use element centered finite volume
discretization because there sub-control volumes are identical to full
control volumes. In particular, ebos -- and by extension `flow_ebos`
-- is unaffected because it does not even use that code.
the groundwater problem should be symmetric because it uses an
incompressible fluid, is a single phase problem and uses the
immiscible model. (i.e., there should never be a difference between
the upstream and the downstream cells.)
the main purpose of this commit is to have a test that uses a linear
solver wrapper which was generated by the internal
EWOMS_WRAP_ISTL_SOLVER macro.
this gets rid of the ugly red and green boxes around references. Note
that for some reason, hyperlinks do not seem to work anyway and that
using pdflatex directly does not work either :/
TeXLive 2016 complains about \it and \bf.
Also, this patch adds a simple bash script to create the handbook from
its LaTeX sources. Note that this script does *not* attempt to detect
if all prerequisites (in terms of binaries and LaTeX packages) are
properly available.
... and use the restarted GMRES solver in conjunction with a ILU-2
preconditioner for the water-air unit test.
I do not really recommend using these solvers because BiCGSTAB tends
to be 20% to 30% slower than our home-brewn implementation (this is
because the dune-istl solvers cannot use custom convergence criteria),
but dune-istl offers more choices than just BiCGStab and this
functionallity could be helpful when debugging issues related to
solving the linear systems of equations.
Note that regardless of how pedantic the interpretation of DUNE's
license is, there are no licensing issues with this code because we do
not distribute any files derived from DUNE anymore.
i.e., the solvers.hh file is removed. The main reason for this is that
it avoids having to distribute a file with a potentially incompatible
license (i.e., GPLv2 + template exception vs GPLv2+), but the
home-brewn bicgstab solver also seems to perform a tiny bit better.
i.e., using clang 3.8 to compile the test suite with the following
flags:
```
-Weverything
-Wno-documentation
-Wno-documentation-unknown-command
-Wno-c++98-compat
-Wno-c++98-compat-pedantic
-Wno-undef
-Wno-padded
-Wno-global-constructors
-Wno-exit-time-destructors
-Wno-weak-vtables
-Wno-float-equal
```
should not produce any warnings anymore. In my opinion the only flag
which would produce beneficial warnings is -Wdocumentation. This has
not been fixed in this patch because writing documentation is left for
another day (or, more likely, year).
note that this patch consists of a heavy dose of the OPM_UNUSED macro
and plenty of static_casts (to fix signedness issues). Fixing the
singedness issues were quite a nightmare and the fact that the Dune
API is quite inconsistent in that regard was not exactly helpful. :/
Finally this patch includes quite a few formatting changes (e.g., all
occurences of 'T &t' should be changed to `T& t`) and some fixes for
minor issues which I've found during the excercise.
I've made sure that all unit tests the test suite still pass
successfully and I've made sure that flow_ebos still works for Norne
and that it did not regress w.r.t. performance.
(Note that this patch does not fix compiler warnings triggered `ebos`
and `flow_ebos` but only those caused by the basic infrastructure or
the unit tests.)
v2: fix the warnings that occur if the dune-localfunctions module is
not available. thanks to [at]atgeirr for testing.
v3: fix dune 2.3 build issue
for some reason, there are differences between my laptop with
optimizations and my workstation in debug mode. since the results look
_very_ similar in paraview, let's treat them both as equally valid.
10^-4 lead to sporadic results if the final tolerance of the solution
really was 10^-4. (it currently is usually better because each time
step experiences an additional update after the Newton method deems it
to be converged.)
as a side effect, two-point gradients are now used by default for the
vertex-centered finite volume discretization. (because P1-FE gradients
require the FE shape functions and those are provided by
dune-localfunctions.)
as a consequence, this triggered an update of quite a few reference
solutions: the differences are measurable, but as far as I can see,
the results are compareable. also, this commit regresses the
performance of the test for the reservoir problem with the vertex
centered finite volume scheme a bit. While I would not bet a house on
the reason, I'm pretty sure that this is caused by the switch from P1
FE gradients to two-point ones.
Note that even though I'm the author of this patch, it shamelessly
rips off substantial parts of the @dr-robertk's patch:
https://github.com/OPM/ewoms/pull/69
