Table of Contents

Name

potlist - list potential value and forces of a potential descriptor

Synopsis

potlist potname=name [parameter=value]

Description

potlist calculates the value of the potential value in (a) user specified position(s). The potential is obtained from data file in standard potential(5NEMO) format.

In addition to the potential value, the forces, it’s derivatives and the poissonian density are calculated. The total table will hence contain: x, y, z, ax, ay, az, phi, phixx, phiyy, phizz, rho, dr, time.

Parameters

The following keywords are recognized in any order if the keyword is also given:
potname=name
Generic name of the file which contains the description of the potential. Some potentials require an addition data-file, see keyword potfile=. [default: none].
potpars=parameters
List of parameters for the model. Will all be interpreted as double precision numbers. If less than the required number of parameters are given, the remainder will be taken from default settings in the potential routine. When too many are given, the remaining are ignored. The first parameter, currently ignored, is reserved for pattern speed, unless overridden with the omega= keyword described below. [default: as defined by potential routine].
potfile=datafile
Optional extra datafile which some potential descriptors use. Some files need a list of spline fitted points, others need an N-body snapshot etc. Most potentials will ignore this keyword though. [default: not set].
x=x-pos
X-position(s) where potential, forces and density are calculated. If more than one value is given, it must be consistent with the number given in the other space coordinates. See nemoinp(1,3) for rules to provide multiple values. [default: 0.0].
y=y-pos
Y-position(s). See X. [default: 0.0].
z=z-pos
Z-position(s). See X. [default: 0.0].
t=time
If applicable, the time at which the potential is to be calculated. [default: 0.0].
dr=value
Differential in position which is used to numerically compute the force derivatives to compute the Laplacian. The poissonian density is then obtained after division by 4-pi. If no number is given, the densities are not computed, and only position, accelerations, potential and time are returned. Default: not used.
omega=pattern_speed
Override value for the pattern speed. Normally the pattern speed is defined by the first argument in potpars=, but this allows you to override. Forces and potentials are correctly displayed in the rotating frame of reference, but computing poissonian densities would not make sense without setting omega=0. Default: not used.
format=fmt
Format used in printf(3) statement to print value. If no separator is provided, a space will be used. [Default: %g]
ndim=2|3
Number of dimensions used in Poissonian density computation. Should be 2 or 3.
ouble=t|f
Force usage of Float or Double potentials. By default autodetected. Old potentials (prior to 2001) are only available in double, which is the default.

Caveat

The keyword double= can force a float potential to be treated as a double potential, and vice versa. Results can thus be meaningless in these cases, or the program will look in untrusted memory and coredump.

See Also

potccd(1NEMO) , potential(3NEMO) , potential(5NEMO)

Author

Peter Teuben

Files


~src/orbit/potential    original sources

Update History


13-Jul-87    V1.0: Original created    PJT
8-Apr-88    V2.0: added ’name’ parameter for hackforce    PJT
5-May-88    V2.1: small mods, renamed keywords    PJT
9-feb-90    V3.0: added time dependant options, renamed keywords    PJT
26-jun-90    V3.1: can give whole array of input positions    PJT
15-oct-93    V5.1: new method(s) of getting pattern speed    PJT
17-feb-94        V5.2: added ndim=    PJT
18-sep-01    V4.0: handle both _float and _double potentials     PJT


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