A workshop dedicated to the Theoretical Virtual Observatory will take place at IAP on April 5-6th.
The goal is to bring together experts of the Virtual Observatory and theoreticians who would like to make results of their simulations (e.g. databases or catalogs) or numerical codes available to the worldwild astronomical community.
GRAFIC1 files are little endian unformatted Fortran files. In these files, the seven fields (ic_deltab, ic_velbx/y/z, ic_velcx/y/z) are described on a regular grid.
The seven outputs follows the same structure:
np1,np2,np3: 3 integers describing the size of the grid along the 3 directions
dx: the size of a grid element in Mpc/h
x1o,x2o,x3o: the coordinates of the grid’s origin
astart: the initial scale factor
omegam, omegav: the density parameters
h0: the hubble constant
np1*np2matrix, i.e. ICs are organised in layers along the z-direction. This feature can be easily used to spare memory usage when these files are manipulated, since layers can be uploaded sequentially in memory. Velocities are in km/s while density is expressed in terms of density contrast.
The following Fortran example shows how to read such files:
White Noise files follow the same data structure, with a different header format. The header stands as a single record which contains the following variables:
np1,np2,np3: 3 integers describing the size of the grid along the 3 directions.
iseed: 1 integer coding the seed of the random generator
Subsequent layers are organised in the same way as the density and velocities fields.