Coulomb scattering is now fully conservative thanks to the method in
lemos2009small.
The trick was to conserve the momentum and energy of ALL particles
involved in the scattering in each cell.
The substeps in Coulomb collisions have been removed as they are no
longer necessary.
Still some issues with e-i, but I don't know right now.
Now per each Coulomb collision process there is the possibility to do
sub-steps. This helps in improving accuracy without reducing the time
step of the problem.
I was having a lot of issues trying to get quasi-neutrality with the
injection of electrons and ions. Main issue was a definition of the
direction of injection. This should be fixed now (tested in 1D).
Added a definition for Half-Maxwellian velocity distribution.
WARNING: I'm still not happy at all about the definition of the
direction of injection and the velocity definition to be in that
direction so I might change it at some point (for example take into
account the sign of each direction in the thermal part of the velocity)
I am doing a trick in which I ensure that energy is conserved for
Coulomb collisions. This was not happening and what an issue for
different mass ratios. Still, this can cause an issue on getting the
right relaxation rates, still necessary to check it.
First attemp for Coulomb collisions based on the moments distribtuions.
Still the method is not done and far from being complete but input
options and basic math are implemented.
Probes are now written at the 0 iteration.
Additionally, and this shouldn't be done, some small changes to the quad
elements. This should be done in a separate commit, but I'm lazy.
For some reason the connectivity for collision meshes was not being
properly assigned.
Also, the first subroutine to read information from .vtu files as
initial states has been added.
It is currently giving wrong results.
Moving forward making vtu an independent format.
Now fpakc can generate nodes and edges from vtu input.
Next step is cells.
Some minor corrections in gmsh2 format to unify statements.
The reading of meshes needs a good overhaul.
Testing all geometries with vtu is gonna be fun...
Now, if no normal is provided to an injection in the input file, the
velocity direction of the particles is chosen to be the surface normal.
This allows to inject particles from curves, corners... without having
to provide a direction or declaring multiple injections.
While testing the examples distributed with the code, a few errors were
found and fixed, mostly related with the K matrix in 1D geometry and
reading values from initial conditions for species.
Finalysing first step of performance improvement focusing on reducing
iteration CPU time by improving calculation of basic element functions,
which took a lot of the CPU time
I noticed that phy2logquad had a lot of overhead. Trying to reducing it
by simplifying calls to fPsi, dPsi and such.
The function for fPsi has been made so no memory is allocated and works
under the assumption that the input array has the right size (1:numNodes)
