Dear Users,


in case you used the ZigZag current deposition scheme and *all* of the
following criteria apply to you, you will be affected by a bug that René
Widera discovered today:

  - 2D3V
  - ZigZag current deposition scheme for charged species
  - relevant v.z component in particles (e.g., warm plasma start)

  https://github.com/ComputationalRadiationPhysics/picongpu/pull/823

Currents along the z-direction where over-estimated by a factor 2.

The ZigZag current deposition scheme was a generalization of three
papers that we implemented past year as an alternative to the Esirkepov
scheme. It provides about a factor 1.6 speedup due to reduced memory
access and scales better than the Esirkepov implementation with number
of particles per cell.

It is *not* enabled by default yet.
If you did not change the value (UsedParticleCurrentSolver) in
`species.param` , which was in earlier versions in
`componentsConfig.param`,  you will *not* be affected.

As soon as #823 is merged, `dev` will not be affected any more. The fix
will also be back-ported to the upcoming `0.1.0` release of PIConGPU.


Best regards,
Axel
--

Axel Huebl
Phone +49 351 260 3582
https://www.hzdr.de/crp
Computational Radiation Physics
Laser Particle Acceleration Division
Helmholtz-Zentrum Dresden - Rossendorf e.V.

Bautzner Landstrasse 400, 01328 Dresden
POB 510119, D-01314 Dresden
Vorstand: Prof. Dr.Dr.h.c. R. Sauerbrey
          Prof. Dr.Dr.h.c. P. Joehnk
VR 1693 beim Amtsgericht Dresden