Reading and Writing Data

OpenCosmo defines a data format for storing simulation data in hdf5 files. A dataset in this format can be transformed and written by the OpenCosmo library to produce a new file that can be read by others (or yourself at a later date!) using the library.

Options for Reading Data

Any single opencosmo file can be open with opencosmo.open(). This function will parse the structure of the file and return the appropriate object, such as an :py:class`opencosmo.Dataset` or opencosmo.StructureCollection

import opencosmo as oc

ds = oc.open("haloproperties.hdf5")

You can also use open as a context manager to automatically close the file when you’re done with it:

import opencosmo as oc
with oc.open("galaxyproperties.hdf5") as ds:
    print(ds.data)

When opening multiple files that are linked to each other, use opencosmo.open_linked_files()

Writing Data

Writing data to a new file is straightforward:

oc.write("my_output.hdf5", ds)

Transformations applied to the data will propogate to the file when written, with the exception of oc.Dataset.with_units(). When you write data, it will always be stored in the unit convention of the original raw data.