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snapadd - adds N-body systems on top of each other
This program adds up N-body systems by appending
a number of snapshots to each other. Optionally the snapshots can be re-centered
to their center of mass, though this is not the default. If the input files
contain more than one snapshot, they are concurrently added (copying over
the timestamp of the snapshot in the first file) until any of the files
If only two snapshots are added, snapstack(1NEMO)
some more options, such as adding a relative shift in phase space. If more
complicated shifts are necessary, snapshift(1NEMO)
can be used before snapadd.
If you want to keep the snapshots separate, simple unix tools like cat(1)
will work fine. For some of the older NEMO programs, embedded history could
throw them off, and csf(1NEMO)
should be used to create cleaner snapshots.
See an example below.
The following parameters are recognized
in any order if the keyword is also given:
Snapshots only copy accross
Mass (if they have it) and PhaseSpace.
- in=in1, in2, ..
- A number of input
files can be supplied, separated by comma’s. They must all be in snapshot(5NEMO)
format [no default].
- output file, in snapshot(5NEMO)
- If true, translate to center of mass before output.
- Message header appended to any existing ones
in the input files [default: none].
Although snapadd merges snapshots, if you want separate snapshots
with their own timestamps, unix cat(1)
will do just fine:
% cat snap1 snap2 snap3 > snap.all
though this might throw off some older NEMO programs that cannot handle
embeddded history tags. If so, filter them through csf(1NEMO)
% csf snap1 snap.all
% csf snap2 - item=SnapShot >> snap.all
% csf snap3 - item=SnapShot >> snap.all
6-May-87 V1.0: created PJT
8-Mar-87 V1.1: data history PJT
xx-xxx-87 snapstack written by JEB
18-nov-90 V2.0: snapadd revived with multiple input PJT
13-may-92 V2.2: added concurrent reading PJT
15-jul-07 added examples (while at V2.5b) PJT
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