reset.cm

Routine, designed to reset the center of mass (CM) of the initial conditions (ICs) of an N-body simulation. The CM position and velocity are both shifted to (0,0,0).

Run simple direct gravitational N-body simulations. The package can access different external N-body simulators (e.g. GADGET-4 by Springel et al. (2021) <doi:10.48550/arXiv.2010.03567>), but also has a simple built-in simulator. This default simulator uses a variable block time step and lets the user choose between a range of integrators, including 4th and 6th order integrators for high-accuracy simulations. Basic top-hat smoothing is available as an option. The code also allows the definition of background particles that are fixed or in uniform motion, not subject to acceleration by other particles.

Danail Obreschkow

nbody

Gravitational N-Body Simulation

reset.cm function

<dl><dt>sim</dt>
<dd>list of m, x, v or list with a sublist "ics", made of m, x, v, where
<code>m</code> = N-vector with the masses of the N particles. Negative masses are treated as positive masses of same magnitude, since negative masses normally represent positive background masses in the nbody package. 
<code>x</code> = N-by-3 matrix specifying the initial position in cartesian coordinates 
<code>v</code> = N-by-3 matrix specifying the initial velocities </dd></dl>

Arguments

Author

Move center of mass to the origin — reset.cm

<dl>

<dt>sim</dt>
<dd>list of m, x, v or list with a sublist "ics", made of m, x, v, where
<code>m</code> = N-vector with the masses of the N particles. Negative masses are treated as positive masses of same magnitude, since negative masses normally represent positive background masses in the nbody package. 
<code>x</code> = N-by-3 matrix specifying the initial position in cartesian coordinates 
<code>v</code> = N-by-3 matrix specifying the initial velocities </dd>

</dl>

reset.cm: Move center of mass to the origin

Description

Usage

Value

Arguments

Author