ParticleIntegrator: Output

The type of output (text or binary) can be chosen in the configuration file.

Text output

Text output consists of a number of text files, one per computed particle, that are located in the OUTPUT directory. Each text file, by default, has the filename of the input file with an added number for the particle number at the end (e.g. particleinputname_#42.txt).

It contains the tab-separated states (position, speed, et) of the particle at several points in time. The number of saved states, as well as the starting time from which the states are saved, can be controlled in the configuration.

Benefits of the text output

• Higher precision
• Easy to read on any system, with any text editor

Binary output

The binary output is one single file containing the information of all the input particles in 32 bit floating point format. The output file is always named binary_output.ctwu for easier handling on the Constellation platform.

It contains information in the following order:

A global header for the output file:

• Number of the first particle
• Number of the last particle
• Particle mass
• Particle density
• Beta
• Ejection time of the first particle
• Ejection time of the last particle

Then, for each particle, a particle header:

• empty
• empty
• empty
• empty
• Number of this particle
• Multiplication factor
• empty

Followed by the states saved for this particle (repeated for all the states that were saved):

• x
• y
• z
• vx
• vy
• vz
• et

This binary output is generated from the text output at the end of the simulation of all particles, so don't be confused if the application starts producing text output files even though it is configured to give binary output. This makes it easy to check the output while the application is running.

The reason for the reduced accuracy of the binary output (float32 instead of float64) is a reduction in file size for saving a large number of particle states and particles. It also makes sending the files between clients and servers easier and faster.

Benefits of the binary output

• Faster to transfer and read into tools like MATLAB
• Smaller in file size
• Contains additional information about the particles