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eaglesnap - convert EAGLE hdf5 snapshots to NEMO snapshot format


eaglesnap [parameter=value]


eaglesnap converts an HDF5 snapshot from the EAGLE simulation in a NEMO snapshot format. Various selections are possible: an X,Y,Z region, particle type (enforced), group and subgroup.

Currently only mass and phasespace coordinates are converted. This is still done in code units, in a future option conversion to astrophysical units will be possible.

debug=1 will also list the datasets contents of the HDF5 file.


The following parameters are recognized in any order if the keyword is also given:
Input file (HDF5). Only one of the HDF5 parts needs to be given. The eagle_read access routines know how to find all of them. No default.
Output file, in snapshot format. No default.
Which particle type 0-5 (0=gas, 1=DM, 4=star, 5=BH) [0]
Select rectangular region (xmin,xmax,ymin,ymax,zmin,zmax). If two values are given, they are xmin,xmax and replicated as a cube for Y and Z. If one value is given, this is xmax, and 0,xmax is selected and again replicated for Y and Z. [0,10,0,10,0,10]
Select this group (-1 means all,1..NG are validm 2^30 is no group)) [-1]
Select this subgroup (-1 means all, 0..NSG-1 are valid, 2^30 is no subgroup) [-1]
Convert to Mpc, Msol, .... - not implemented yet.
If given, it will center the selected particles here (3 values, in code units), meaning the coordinated will be shifted such that the center will be (0,0,0). You will also need to specify a boxsize, since the grid is periodic. [Default: not used]
Size of the box if center= is used. This value is also inside the HDF file, but not available via read_eagle. Default: not used, required if center= is given.
A cheat by which the total dark matter (DM) mass can be set. Once eagle_read() can grab those from the header, this keyword will not be needed anymore and likely disappear. Current default: 1


Assuming you have a username/password for database access, the following commands show some of the things you can do
    wget --user=... --ask-password --content-disposition 
    tar xvf RefL0012N0188_snap_028.tar
    h5dump -n RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
    eaglesnap RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
snap1  ptype=0 region=2
Data are taken from a typical co-moving cosmological grid. Objects near the edge, may seem to wind up in two places, as can be seen in the following example snapshot:
    eaglesnap RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
snap2 0 group=2
    snapplot3 snap2 xrange=-10:10 yrange=-10:10 zrange=-10:10

See Also

snapshot(5NEMO) , eagle(5NEMO) - EAGLE snapshots - The EAGLE Project - EAGLE database access - library used - MARTINI


NEMO/usr/eagle    directory with support to install EAGLE tools
NEMO/src/nbody/io/eaglesnap.c    code for eaglesnap


This will be the section for eagle(5NEMO) , but now it’s here

RefL0012N0188 is the small volume (12Mpc) reference run. It has 29 slices in z, ranging from slice 0 at z=20 to slice 28 at z=0.0. Slice 27, the one but most recent slice, is at z=0.10. The number of particles is (188^3) 6,644,672 per species (gas and DM). At z=0 one can see 6,381,559 gas, 262380 stars, and 547 BH, this still 186 short, so did some merge? This means SFE = 4.0% Each snapshot comes in "nfiles" parts, e.g. snap_028_z000p000.0.hdf5, snap_028_z000p000.1.hdf5, ... snap_028_z000p000.15.hdf5. The read_eagle routines will automatically read of all these in order to populate the snapshot correctly.

Simulations with L=12, 25, 50, 100 co-moving Mpc are available.


Peter Teuben

Update History

02-Nov-19    V0.1 Created        PJT

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