Header image PMss files

There are three formats for files, which store all information on particles in the simulation. All files are unformatted Fortran files written using big-endian coding.

  • MPI:    files used by ART when it was running. All coordinates and velocities are double precision variables + particles IDs
  • PM : single precision, direct-access files. Particles are sorted by their IDs. The most compact form of data
  • PMss: single precision, sequential files, which include buffers surrounding each domain. Each file can be analyzed independently from the others.


    The whole computational box is evenly devided into 5x5x5 =125 boxes. Each box has all particles in its main domain of 50x50x50 Mpch plus each box has particles in buffer of width 2.2Mpch surrounding its main domain on all sides. Thus, the total size covered by each file is (54.4Mpch)**3.

    Files are has names: PMss.xxxx.yyyy.DAT, Where xxxx code the order of the box and yyyy is the snapshot number. If (i,j,k) is a triplet, which indicates position of the box (i,j,k = 1-5), then xxxx = 0+i+5(j-1)+25(k-1).

    This is an example of a code, which reads the data. It should be used as a template for building your own code to read and analyze the particles data.

    Format of the files: