Prerequisite

For generating WarpX streamlines using this code you'll require:

1. Boost (program options)
2. VTK-m version 1.7

Sample WarpX data is available here There are two different types of data:

1. Species : These are the charged particles that will be used for advection.
2. Fields : These are the electric and magnetic fields that we'll use for velocity calculation.

To execute the code after compilation you can simply execute the following:

./advection params

params being the file containing the input parameters for the example. The parameters that are included for the data at the link above are

data=data/vtk_fields_0000250.vtk                                                
steps=120                                                                       
length=0.1                                                                      
seeds=50                                                                        
seeddata=data/vtk_specie_beam_0000250.vtk                                       
sampleZ=-6.5000e-05:-5.00668e-05                                                

Warp X data

The data in the section above is only a single slice, More WarpX data is available here

All the data is available as hdf5 files. They need to be converted into vtk in order to use the code example from this repository.

For converting the WarpX files to VTK you'll need to perform the following steps.

1. Download and install opmd2VTK More instructions on the installation can be found here

2. Convert the data using the following script

import sys
import os
import os.path

opmdpath='/home/abhishek/repositories/opmd2VTK/install/lib/python3.6/site-packages/opmd2VTK-0-py3.6.egg'
pyvtkpath='/home/abhishek/repositories/opmd2VTK/install/lib/python3.6/site-packages/PyVTK-0.5.18-py3.6.egg'
sys.path.append(opmdpath)
sys.path.append(pyvtkpath)

from openpmd_viewer import OpenPMDTimeSeries
from opmd2VTK.pyvtk import Opmd2VTK

datadir = sys.argv[1]
if os.path.isdir(datadir) and os.access(datadir, os.R_OK):
  ts = OpenPMDTimeSeries(datadir)
  conv = Opmd2VTK(ts)
  for i in range(0, len(ts.iterations)):
    conv.write_fields_vtk(iteration=ts.iterations[i], format='binary')
    conv.write_species_vtk(iteration=ts.iterations[i], format='binary')
else:
  print("Data directory cannot be accessed")
  sys.exit(-1)

The script requires the path to the directory which contains all the WarpX hdf5 files as an input. After extracting the archive from the link you can execute

python converter.py diag_openpmd

That's all :)