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snapcmphist - compare two N-body snapshots and plot histogram
snapcmphist
in1=snap_file in2=snap_file [parameter=value] ...
snapcmphist like
snapcmp(1NEMO)
is a flexible tool for comparing two N-body snapshots on
a particle by particle basis, but snapcmphist plots a histogram of the
resulting values. An arbitrary ``observable'' defined in terms of the basic
components of a body(3NEMO)
may be specified for the comparison. Particles
are compared by differencing their observables, or by computing the observable
applied to a differenced particle. These options cover most of the common
methods of comparing N-body snapshots. The default settings compute the
magnitude of the configuration-space displacements between each pair of
particles.
The following parameters are recognized.
- in1=snap_file1
- in2=snap_file2
- Input data is read from snap_file1 and snap_file2, which
must be in snapshot(5NEMO)
format. Default: none.
- time1=time_range1
- time2=time_range2
- Data with time values within time_range1 and time_range2 will be read from
snap_file1 and snap_file2, respectively. At present only the first pair
of frames within these ranges will be analyzed. Default: "all", which has
the effect of using the first pair of frames in the files.
- obs=obs_expression
- obs_expression is the observable used to compare the particles. See bodytrans(1NEMO)
for the form of obs_expression. Default: r, which compares the positions
of particles.
- diffpart=flag
- If flag is true, particles are compared by subtracting
the components of one from the components of the other, and evaluating
the observable obs on this ``differenced particle''. Otherwise, obs is evaluated
for each particle, and the results are differenced. Default: true.
- relative=flag
- If flag is true, the differenced observable is divided by the value of
obs computed from the particle in snap_file1. Otherwise, the differenced
observable is used. Default: false.
- nbins=num_bins
- Number of equally-spaced
bins to use for histogram. Default: 8.
- xrange=x_axis_range
- Range of values
covered by histogram; of the form low:high. Default: 0.0:1.0.
- xlabel=x_axis_label
- Label for x-axis. Default is obs_expression.
- nxticks=num_x_ticks
- Number of
equally-spaced tickmarks along x-axis. Default: 3.
- ymax=max_y_value
- If specified,
use as max value on vertical axis; if not, program uses highest histogram
bin to pic scaling. Default: none.
- ylabel=y_axis_label
- Label for y-axis.
Default: N.
- nyticks=num_y_ticks
- Number of equally-spaced tickmarks along
y-axis. Default: 3.
- headline=
- Verbiage at the top right of the graph. Default:
none.
snapcmp(1NEMO)
, snapdiff(1NEMO)
, bodytrans(3NEMO)
, snapshot(5NEMO)
Joshua E. Barnes.
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