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rundiskfit - NEMO frontend to run Spekkens & Sellwood’s 2012 diskfit code


rundiskfit [parameter=value]


rundiskfit is a NEMO frontend to diskfit, which supersedes their previous velfit (see runvelfitss07(1NEMO) ) release.

diskfit implements procedures for fitting non-axisymmetries in either kinematic or photometric data, as first described in Spekkens & Sellwood (2007) for velocity fields and Reese et al. (2007, SS07) for images. DiskFit supercedes velfit 2.0 in that it implements a refined version of that code to fit kinematics, and corresponds to the first public release of the image fitting code described in R07. DiskFit improves upon the functionality of velfit described in SS07 and Sellwood & Zanmar Sanches (2010) as well as that for image fitting described in R07, by carrying out an optional seeing correction for both kinematic and photometric fits.

Radial (m=0) flow can be fitted by setting flags(4) , whereas bisymmetric (m=2) or lobsided (m=1) flow with flags(5) (see flags= below). The code is usually not well converging when fitting both. For more details and a full explanation of the parameters, Spekkens and Sellwood (2007ApJ...664..204S) and the Users Guide on the DISKFIT website.

The current frontend is under development, the only reliably way to run the examples is via the inp= keyword.


The following parameters are recognized in any order if the keyword is also given:
This is currently the only supported option. This is the input parameter file, as supplied to diskfit.
input velocity field. The first 4 lines are completely ignored, each subsequent data line must be X,Y,V,DV in 4F10.2 format. Note X is positive to the west. Up to 50,000 points can be read in the default compilation. No default.
output model field. No default.
output parameter file. No default.
center of velocity field. Note X is positive to the west [0,0].
systemic velocity [0]
(kinematic) position angle of disk (E of N), the usual convention applies where this means the receding side of the disk [0]
inclination angle of disk [0]
ISM turbulence [0]
Siz flags which to be fitted/done: geom (inc and pa), center, vsys, radial (m=0), lobsides/bisymmetric (m=1,2...), error estimates. [1,1,1,0,0,0]
harmonic order of bar perturbation (1 or 2). [2]
Random Seed [-50]
Number of bootstrap samples if errors (flags(6) set) are calculated. Note using bootstrap will result in a large runtime. [200]
correlation length, in case bootstrap is used [1.0]
Radius beyond which no non-circular rmotions fitted [50]
Ring Radii at which velocity field components are are extracted.
Only used for ASCII tables, if the program should attempt to regrid the data in a Default: t.
name of VELFITSS07 executable. It will have to be found in the user’s $PATH. Note that although the original name of the SS07 is velfit, this conflicts with velfit(1NEMO) and within NEMO we normally rename the SS07 version fo velfitss07. [velfitss07]


Here are the 5 examples from the Users Guide:
ex 1a: rundiskfit inp=EXAMPLE/PHOT/phot_disk.inp
ex 1b: rundiskfit inp=EXAMPLE/PHOT/phot_full.inp
ex 2a: rundiskfit inp=EXAMPLE/VELS/FITS/velsf_disk.inp
ex 2b: rundiskfit inp=EXAMPLE/VELS/FITS/velsf_bi.inp
ex 3 : rundiskfit inp=EXAMPLE/VELS/TEXT/velst_err.inp

Note you have to run them from a directory where EXAMPLE is a subdirectory.


The 5 benchmarks (1a, 1b, 2a, 2b and 3a) reporting pure user times:
CPU/speed        test1a    test1b    test2a    test2b    test3a
core2d T7300 @ 2.0 GHz    4.3    220.6    15.4    7.6    45.2 "2007 linux laptop [v1.0]"
i7/870 @ 2.93 GHz    2.1    463.7    8.6    4.8    27.9 "2010? linux desktop"
i7/3770 @ 3.50 GHz    1.7    77.6    7.3    4.1    26.5 "2012 linux desktop"
i7? mac @ x.x GHz    2.7    124.9    9.7    5.2    36.4 "2010? mac desktop"
i7-3630QM @ 2.40GHz    2.3    144.5    1.0    6.0    29.2 "2014 linux laptop [v1.1]"    

See Also

rotcur(1NEMO) , velfit(1NEMO) , runvelfitss07(1NEMO) , rotcurshape(1NEMO) , rundiskfit12(1NEMO)

2007ApJ...664..204S (Spekkens & Sellwood, 2007)
2007AJ....133.2846R (Reese, Williams, Sellwood, Barnes & Powell 2007)
2012MNRAS.....  (Kuzio de Naray, Arsenault, Spekkens, Sellwood, McDonald, Simon,
Teuben 2012)


NEMO/usr/spekkens/velfit    - original SS07 code/examples (see their WEBSITE)
NEMOBIN/velfitss07    - SS07 executable (see also exe=)
NEMO/src/image/rotcur    - NEMO frontends


The parameter file ( is in the local run directory, and is silently overwritten. This will hamper running the program in parallel.


Peter Teuben

Update History

13-sep-2012    V1.0 : frontend for diskfit V1.0  (July/Aug 2012)    PJT
7-aug-2014    V1.1 : various updates for V1.1 (May 2013)    PJT

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