description: Increases the number of particles in a particle input file by
successively doubling the number. Intended to be used to increase the number of particles
produced by a photoinjector simulation to improve stability of CSR and LSC simulations.
The algorithm is as follows:
For each doubling, insert a new particle ``near'' every pair of existing particles in time.
The particle has a new t value, but the same (x, xp, y, yp, p) as one of the original particles.
Bin the beam according to t into a large number of bins. Randomize the assignment of p values
relative to other coordinates across particles in the same bin, while additionally adding a
small random value to each p value.
doubleDist6 -input name -output name -doublings number -nt bins
input -- A particle distribution file, such as might be used with sdds_beam.
output -- A particle distribution file, such as might be used with sdds_beam.
-doublings n -- The number of times to double the size of the distribution.
The number of particles in the output file is times the number in the input file.
-nt bins -- The number of time bins to use for momentum randomization. This
helps to avoid having many particles with exactly same momentum.