Fbpic

This release introduces various improvements to FBPIC:

- The initial space-charge calculation produced unphysical fields for
high-energy beams with space-charge. This is now fixed ; see
[289](https://github.com/fbpic/fbpic/pull/289)

- More flexible ionization API: The user can now store the electrons from
different ionization levels into different species. In addition, the user
can now set a maximum level of ionization ; see
[288](https://github.com/fbpic/fbpic/pull/288) and
[283](https://github.com/fbpic/fbpic/pull/283)

- Improved restart from checkpoints: for safer use, the restart now requires
that the number of species is the same in the simulation
(when calling `restart_from_checkpoint`) and in the checkpoint file.
(New species can nonetheless be added after calling `restart_from_checkpoint`.)
; see [278](https://github.com/fbpic/fbpic/pull/278)

- The plasma can now be initialized with a non-zero temperature
(see the documentation of the method `add_new_species`) ; see
[277](https://github.com/fbpic/fbpic/pull/277)

- There is a new diagnostic (`SpeciesChargeDensityDiagnostic`), which allows
to have the charge density of *one given* species ; see
[287](https://github.com/fbpic/fbpic/pull/287)

Minor fixes:
- More efficient CPU execution by treading the `erase` function ;
see [276](https://github.com/fbpic/fbpic/pull/276)
- When using `FBPIC_DISABLE_THREADING=1`, the code will not need to compile
for each execution, thereby allowing faster turnaround ; see
[279](https://github.com/fbpic/fbpic/pull/279)

This is a minor release.

It fixes a few bugs:
- the restart mechanism for an arbitrary number of azimuthal modes ; see
[275](https://github.com/fbpic/fbpic/pull/275). Before this, restarting
simulations worked only when using up to 2 azimuthal modes.
- the diagnostics of `rho` for multi-GPU simulations ; see [265](https://github.com/fbpic/fbpic/pull/265)

In addition, this release introduces the possibility to inject a laser from
a moving antenna ; see [262](https://github.com/fbpic/fbpic/pull/262).

It also introduces a minor change in the `LaserProfile` API:
the user should now pass the propagation direction (i.e. forward-propagating
or backward propagating) to the laser profile directly ; see [260](https://github.com/fbpic/fbpic/pull/260).

This is a bug-fix release. It fixes a bug in the initial space-charge
calculation, that was introduced in version 0.9.1. (Previous versions do
not have this bug ; see [254](https://github.com/fbpic/fbpic/pull/254) for
more details.)

In additional more laser profiles were added. This includes:
- Donut-like Laguerre-Gauss laser profile [257](https://github.com/fbpic/fbpic/pull/257)
- Flattened Gaussian laser profile [244](https://github.com/fbpic/fbpic/pull/244)

This is a minor release, which includes miscellaneous improvements to fbpic:

Bug fixes:
- The restart mechanism now works with ionizable particles. (See [237](https://github.com/fbpic/fbpic/pull/237))
- For multi-CPU/GPU simulations using the Galilean scheme, the stencil extent and corresponding number of guard cells is now properly calculated. (See [240](https://github.com/fbpic/fbpic/pull/241))

In addition, various improvements have been made to the documentation. (See [239](https://github.com/fbpic/fbpic/pull/239) and [#240](https://github.com/fbpic/fbpic/pull/240).)

Finally, the charge/current deposition is now more efficient on CPU, when multiple species are used (See [234](https://github.com/fbpic/fbpic/pull/234))

This version improves several features related to creation and continuous injection of particles.

New features:
- New species can now be created with the new method `add_new_species` of the
`Simulation` object. (See [228](https://github.com/fbpic/fbpic/pull/228))
This is particularly useful for simulations involving ionization.
(See [231](https://github.com/fbpic/fbpic/pull/231))
- Macroparticles with zero weight will not be created anymore. This saves time
and memory when running simulations where the plasma `dens_func` is 0 over
long distances ([223](https://github.com/fbpic/fbpic/pull/223)). In addition,
a warning is now printed if the `dens_func` returns negative values
([227](https://github.com/fbpic/fbpic/pull/227)).
- Electron bunches can now be injected through a plane, in order to avoid
space charge effects over long distances in the boosted frame
([186](https://github.com/fbpic/fbpic/pull/186)).
- MPI communications involve less synchronization
([217](https://github.com/fbpic/fbpic/pull/217)) and include support for
GPUDirect ([226](https://github.com/fbpic/fbpic/pull/226)). Note that this is
for testing purposes for the moment. Multi-GPU/multi-CPU are still not
officially supported.
- The default number of guard cells and damp cells has been increased.
([229](https://github.com/fbpic/fbpic/pull/229))

Miscellaneous:
- The style of warnings has been changed ([227](https://github.com/fbpic/fbpic/pull/227)).
- This new release includes the cross-deposition scheme ([202](https://github.com/fbpic/fbpic/pull/202)).
This is for testing purposes for the moment.
- The arrays `z` and `r` of the interpolation grid are now calculated on the fly.
([215](https://github.com/fbpic/fbpic/pull/215))

Bug fixes:
- The restart from checkpoint were slightly incorrect, due to an incorrect
size of the grid, by one cell size ([224](https://github.com/fbpic/fbpic/pull/224)).
This is now fixed.
- Continuous injection (with moving window) used to be incorrect for particles
with different number of particles per cell in z. This is now fixed.
([230](https://github.com/fbpic/fbpic/pull/230))
- Injection of a Gaussian bunch in the boosted frame did not involve checking
that the particles are in the correct local subdomain. This is now fixed.
([232](https://github.com/fbpic/fbpic/pull/232))

This version allows FBPIC to run with an arbitrary number of azimuthal modes.
(The previous versions only worked with 2 modes: m=0 and m=1.)

This version also includes various improvements:

New features:
- Threading (on CPU) was only activated for numba 0.34 and numba 0.36. It
is now also activated for versions above 0.36.
(See [199](https://github.com/fbpic/fbpic/pull/199))
- The code can now run in parallel with the `use_true_rho` option
(See [210](https://github.com/fbpic/fbpic/pull/210))
- When using `verbose_level=2`, multi-CPU simulations now print the node
on which each MPI rank is running.
(See [209](https://github.com/fbpic/fbpic/pull/209))

Bug fixes:
- The moving window used to only work in one direction. It can now work in both.
(See [206](https://github.com/fbpic/fbpic/pull/206))
- In a multi-GPU run, the out-of-memory errors will stop the whole simulation,
instead of having other GPUs waiting indefinitely for the one GPU that crashed.
(See [212](https://github.com/fbpic/fbpic/pull/212))
- Version 0.7.1 introduced a minor bug in the GPU current deposition, which
lead to slight differences between the CPU and GPU results.
This has now been fixed. (See [216](https://github.com/fbpic/fbpic/pull/216))
- There was a minor bug in the restart code, which did not update the arrays
of positions of the grid. This was only likely to affect restarts followed
by the initialization of a laser (a rare case). This now fixed by calculating
these arrays on the fly. (See [215](https://github.com/fbpic/fbpic/pull/215))
- The field and particle diagnostics will now automatically convert the input
`period` to an integer, which avoids erratic behavior if a float was provided.
(See [198](https://github.com/fbpic/fbpic/pull/198))