local field map coordinate reference frame

[zhaozhiwen]

gemc 2.3 in JLAB_VERSION 1.3 treats coordinate of local field map relative in its mother volume.
Currently gemc treats coordinate of local field map as absolute coordinate in the root volume and we have to use DISPLACE_FIELDMAP option to load it correctly.
Either way can work and the current one seems less intuitive.

[zhaozhiwen]

here is one example.

https://github.com/JeffersonLab/solid_gemc/blob/master/field/oxford_ptarget.dat
https://github.com/JeffersonLab/solid_gemc/blob/master/geometry/target/solid_SIDIS_target_NH3__geometry_field.txt

this local map with shift z=-350cm is load by this geometry with z=-350cm
it needs the following option to work correctly

my guess is shift inside local map is ignored.

[zhaozhiwen]

I checked source/fields/asciiField.cc
in gemc 2.3, it reads shift,integration,ministep,interpolation from map file
in gemc 2.9, it doesn't read any of those and leave them for external options.
ideally, it should read those from map files as default and use external option as runtime override.