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snapplotedit - display and edit an N-body snapshot file
insnap-file out [parametervalue] ...
snapplot and its relatives
plot a sequence of frames from a standard N-body snapshot file. trakplot
is very similar to snapplot, but does not erase and redraw the screen after
each frame plotted. editplot has the same plotting capabilities as snapplot,
but allows the user to define polygonic areas (using a mouse device), within
which all stars are written out to a file. Arbitrary (algebraic) transformations
from particle coordinates to plotting coordinates may be specified; the
visibility, point type, and color may be controled in the same way.
following parameters are recognized; they may be given in any order.
snapplot handles arbitrary C expressions
by invoking the compiler, which is general but rather slow. To speed things
up, the expressions are first treated as names and checked against a collection
of precompiled expressions stored as ".o" files. If a match is found, the
precompiled object is used instead. Precompiled transformations include:
x, y, z, vx, vy, vz, r, v, vr, vt, jtot, phi, etot, t, and i. A complete
list may be deduced by looking in .../nemo/obj/bodytrans/, which is the default
repository. It is possible to customize your own transformations and mantain
alternate collections; see bodytrans(1NEMO)
for more information.
editplot was invoked, after the usual display has been initialized, the
mouse can be used to define a polygon. At the start of every new polygon
the program should beep for your attention. The LEFT button can then be
used to start and continue entering vertices, and they will also be shown
on the screen; the RIGHT button is used to close the polygon. The MIDDLE
button can be used to ’erase’ previous vertices (as far back as erasing the
initial point, although the already drawn lines cannot be erased from the
- Input data is read from snap-file, which must be in snapshot format. No default.
- The output file, in case editplot was used. It is best to
be in a graphics window, in order to see regular output, such as menus.
- Only plot frames with time values within time-range,
which is of the form, eg, "1.0:1.5,2.5,3.0". The default is "all".
- The value of x-expression is plotted along the X axis. x-expression is a real-valued
C language expression over the real values x, y, z, vx, vy, vz, phi, t,
and the integer value i. The default is x.
- Label for the
X axis. The default is the expression given for xvar.
of values for the X axis, specified either as a single number (in which
case the lower bound is zero) or a pair of numbers separated by a colon.
The default range is -2.0:2.0.
- See above. The default is y.
- Determines the visibility of particles.
expression is a integer expression in the above variables; only points
with non-zero values are plotted. The default is 1.
the point type and size. expression is a real expression in the above variables;
zero means plot a point, positive (negative) means plot a circle (cross)
with size controled by absolute value. The default is 0.
- Determines the point color. expression is a real expression in the above
variables; values between 0 and 1 produce a sequence of saturated colors
starting with red, running through the spectrum, and wrapping back to red.
The default is 0.
- If supplied, this will be the basename of SUN
screendumps stored in rasterfile(5)
format. Various utilities exist to manipulate
rasterfiles, e.g. movie(1NEMO)
. Note that snapplot will in general be used
in sunwindows mode, whereas movie can only run in native SUN fullscreen
mode. Because movie expects the rasterfiles to have basename frame, name
must always be frame if the frame option is used. The default is no frame
After each polygon is closed, the program makes sure all stars
within that polygon are flagged to be copied to the output file at the
end of your session. You can define new polygons in a loop, until you close
a polygon with zero length (using the RIGHT button as initial and last
point of the polygon). The program then copies all stars within all polygons
to the output file.
Plot snapshot file "r100.dat" frame-by-frame, with
Plot radius vs radial velocity at times 2.0 through 6.0:
% snapplot r100.dat
Plot binding energy vs angular momentum, showing only the first 1000 particles:
% snapplot r100.dat xvarr xrange0:2 yvarvr times2:6
NB: this last example assumes that "r100.dat" includes potential data in
addition to the usual phase-space data. The expression specified for visib
will be passed to the C compiler.
The default ranges should depend on the variables plotted.
% snapplot r100.dat xvaretot xrange-4:0 \
xlabel"Binding energy" yvarjtot yrange0:0.8 \
ylabel"Angular momentum" visib"i < 1000"
The basename for rasterfiles for use with movie must always be frame. See
In editplot all snapshots can be edited, but many programs
bomb when subsequent snapshots have more particles than the first one. It
is not advised to use this mode with multiple snapshots in the output file.
Data files with unequal snapshot size have now been taken care of
xx-xxx-86 Original program JEB
xx-jul-87 V1.3 various color updates JEB
23-oct-87 V1.3f added frame= option for movies PJT
xx-xxx-88 V2.0 new filestruct JEB
13-aug-88 V2.1 editplot added to the snapplot family PJT