OSCAR 2013

This document specifies new formats for

These formats aim to be as simple and flexible as possible while still containing all necessary information. Ideally, existing files should be convertible by simply prepending several comment lines.

General guidelines

Shebang line

The shebang line must be the first line of the file. It specifies the file type and order of data columns:

#!OSCAR2013 filetype columns

where

filetype ::= (full-evolution nt nx ny nz | hypersurface | particles) 
columns ::= column1 [column2 ...]

Each columnN is a label for the quantity in that data column. The acceptable columns are different for each file type, see following sections. Columns may be specified in arbitrary order.

File types

Hydro full evolution

The shebang line has the following format:

#!OSCAR2013 full-evolution nt nx ny nz columns

where nt, nx, ny, nz are the total numbers of grid points in each dimension. nz = 1 for boost-invariant hydro. The minimal set of columns is

it ix iy iz : t,x,y,z indices
t x y z     : coordinates of fluid cell
vx vy vz    : fluid flow velocity
e p T       : energy density, pressure, temperature

t x y z may be replaced by tau x y eta.

For example, suppose a hydro code runs on a 51 x 51 x 51 spatial grid, steps of 0.5 fm from -12.5 to 12.5 fm, with 100 timesteps from 0 to 10 fm. The following would be a valid file:

#!OSCAR2013 full-evolution 100 50 50 50 it ix iy iz t x y z vx vy zx e p T
# this is a comment and will be ignored
# data begins on next line
0 0 0 0 0.0 -12.5 -12.5 -12.5 1.0 1.0 1.0 2.0 3.0 4.0
0 1 0 0 0.0 -12.0 -12.5 -12.5 1.1 0.9 1.2 2.2 3.3 4.4
...
1 0 0 0 0.1 -12.5 -12.5 -12.5 1.1 0.9 1.2 2.2 3.3 4.4
...
99 50 50 50 10.0 12.5 12.5 12.5 1.1 0.9 1.2 2.2 3.3 4.4
# the previous line was the last of the event
# now a new event is starting

#!OSCAR2013 full-evolution 100 50 50 50 it ix iy iz t x y z vx vy zx e p T
...

Hydro hypersurface

The shebang format is

#!OSCAR2013 hypersurface columns

The minimal set of columns is

t x y z         : coordinates of fluid cell
vx vy vz        : fluid flow velocity
e p T           : energy density, pressure, temperature
dst dsx dsy dsz : fluid cell normal vector dsigma_mu

For example

#!OSCAR2013 hypersurface t x y z vx vy vz e p T dst dsx dsy dsz
5.0 -6.5 3.0 7.0 -1.0 0.5 2.0 1.0 1.0 1.0 2.0 3.0 4.0 5.0
...

Particle evolution

The shebang format is

#!OSCAR2013 particles columns

The minimal set of columns is

ID          : PDG particle ID
t x y z     : spacetime vector
p0 px py pz : energy-momentum vector

For example

#!OSCAR2013 particles ID t x y z p0 px py pz
211 10.0 5.0 5.0 5.0 10.0 -3.0 -4.0 -5.0
...