‘’gpy’’: the shortcut to open a snapshot¶

pNbody provides a script called gpy that ease the loading of a snapshot and the creation of a pNbody object. From the example directory, you can invoke the gpy command

$ gpy MW_galaxy.hdf5
Python 3.10.12 (main, Sep 11 2024, 15:47:36) [GCC 11.4.0]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.31.1 -- An enhanced Interactive Python. Type '?' for help.

This command launches the IPython interpreter, load the pNbody and numpy modules and creates a pNbody object from the MW_galaxy.hdf5 file. It is thus equivalent to run:

>>> from pNbody import Nbody
>>> import numpy as np
>>> nb = Nbody("MW_galaxy.hdf5")

In the IPython environment you can then directly access the pNbody object via the nb variable:

In [1]: nb.nbody
Out[1]: 20235

Note that gpy comes with a bunch of options. See Scripts for the full documentation.

The --arrays options informs pNbody on the arrays to load:

$ gpy --arrays pos,vel MW_galaxy.hdf5

In this examples, only the coordinates and velocities will be loaded.

The --ptypes options informs pNbody on the type of particles to load:

$ gpy --ptypes 0 MW_galaxy.hdf5

In this case, only gas particles will be loaded.

Finally, an important one is --verbose which sets the verbosity of pNbody. Putting it to 10 sets the highest level of verbosity which can be essential for debugging purposes:

$ gpy --verbose 10 MW_galaxy.hdf5
find_format ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 407): the format file is not gh5
find_format ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 410): The format is swift
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 856): reading header...
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header BoxSize >> boxsize [1500.32945615]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header Command_line >> command_line [b'/home/revaz/local/local2023/soft/python-3.10/local/bin/gpy MW_galaxy.hdf5']
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header Date >> date [b'Sat Nov 16 17:48:23 2024']
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header Flag_Entropy_ICs >> flag_entr_ics [0]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header GitTag >> gittag [b'40dfb622619fd9e69678c1ffa6dbf6601bc22348']
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header MassTable >> massarr [     0      0 100000      0      0      0]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header NumFilesPerSnapshot >> num_files [1]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header NumPart_ThisFile >> npart [  391 17969     0     0  1875     0]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header NumPart_Total >> npart_tot [  391 17969     0     0  1875     0]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header NumPart_Total_HighWord >> nallhw [0 0 0 0 0 0]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header Redshift >> redshift [0.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header Scale-factor >> atime [0.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Header UserName >> username [b'revaz']
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Cosmology Omega_lambda >> omegalambda [0.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Cosmology Omega_m >> omega0 [0.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Cosmology h >> hubbleparam [0.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Units Unit current in cgs (U_I) >> Unit_current_in_cgs [1.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Units Unit length in cgs (U_L) >> UnitLength_in_cm [3.085e+21]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Units Unit mass in cgs (U_M) >> UnitMass_in_g [1.98848e+43]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Units Unit temperature in cgs (U_T) >> Unit_temp_in_cgs [1.]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 890): Units Unit time in cgs (U_t) >> Unit_time_in_cgs [3.085e+16]
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 969): reading units...
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 999): reading particles...
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading pos ptype=0 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading pos ptype=1 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading pos ptype=4 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading vel ptype=0 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading vel ptype=1 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading vel ptype=4 dtype=<class 'numpy.float32'> dim=3
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading mass ptype=0 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading mass ptype=1 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading mass ptype=4 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading num ptype=0 dtype=<class 'numpy.uint32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading num ptype=1 dtype=<class 'numpy.uint32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading num ptype=4 dtype=<class 'numpy.uint32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading rsp_init ptype=0 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading rsp_init ptype=4 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading u_init ptype=0 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading tstar_init ptype=4 dtype=<class 'numpy.float32'> dim=1
loadFromHDF5 ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/main.py", line 1805): loading sp_type ptype=4 dtype=<class 'numpy.int32'> dim=1
read_particles ("/home/revaz/local/local2023/soft/python-3.10/local/lib/python3.10/dist-packages/pNbody/config/formats/swift.py", line 1024): Massarr is not supported! Please specify the mass of all the particles!
Python 3.10.12 (main, Sep 11 2024, 15:47:36) [GCC 11.4.0]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.31.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]:

Scripts¶

`gpy`¶

Usage: gpy [options] file

Options:
  -h, --help            show this help message and exit
  --UnitLength_in_cm=UNITLENGTH_IN_CM
                        UnitLength in cm
  --UnitMass_in_g=UNITMASS_IN_G
                        UnitMass in g
  --UnitVelocity_in_cm_per_s=UNITVELOCITY_IN_CM_PER_S
                        UnitVelocity in cm per s
  --param= FILE         Gadget parameter file
  -t  TYPE, --ftype= TYPE
                        type of the file
  --skip_io_block=STR   Skip IO block (comma separated list)
  --verbose=INT         Define the verbose level (0: minimal, 1: standard, 2:
                        details 10:maximal)
  --exec= STRING        give command to execute before
  --ptypes= STRING      list of particle type to read
  --arrays= STRING      list of arrays to read
  -v  INT               verbosity level

‘’gpy’’: the shortcut to open a snapshot¶

Scripts¶

`gpy`¶

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‘’gpy’’: the shortcut to open a snapshot¶

Scripts¶

gpy¶

`gpy`¶