uvmodelfit Namespace Reference

Functions
def	uvmodelfit

---

Function Documentation

def uvmodelfit.uvmodelfit	(		vis = '',
			field = '',
			spw = '',
			selectdata = True,
			timerange = '',
			uvrange = '',
			antenna = '',
			scan = '',
			msselect = '',
			niter = 5,
			comptype = 'P',
			sourcepar = [1.0,
			varypar = [],
			outfile = ''
	)

Fit a single component source model to the uv data

Fit a single component source model to the uv data.  Three models
are available: P=point; G=Gaussian; D=Disk.  Fitting parameters can
be held fixed.   The results are given in the log and placed in a
components file.

Keyword arguments:
vis -- Name of input visibility file 
        default: none; example: vis='ngc5921.ms'
        
--- Data Selection
field -- Select data based on field id(s) or name(s)
        default: '' (all); example: field='1'
        field='0~2' # field ids inclusive from 0 to 2
        field='3C*' # all field names starting with 3C
spw -- Select data based on spectral window
        default: '' (all); example: spw='1'
        spw='<2' #spectral windows less than 2
        spw='>1' #spectral windows greater than 1
selectdata -- Select a subset of the visibility using MSSelection
        default: False; example: selectdata=True
timerange  -- Select data based on time range:
        default = '' (all); example,
        timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss'
        Note: YYYY/MM/DD can be dropped as needed:
        timerange='09:14:0~09:54:0' # this time range
        timerange='09:44:00' # data within one integration of time
        timerange='>10:24:00' # data after this time
        timerange='09:44:00+00:13:00' #data 13 minutes after time
uvrange -- Select data within uvrange (default units kilo-lambda)
       default: '' (all); example:
       uvrange='0~1000kl'; uvrange from 0-1000 kilo-lamgda
       uvrange='>4kl';uvranges greater than 4 kilo lambda
       uvrange='0~1000km'; uvrange in kilometers
antenna -- Select data based on antenna/baseline
        default: '' (all); example: antenna='5&6' baseline 5-6
        antenna='5&6;7&8' #baseline 5-6 and 7-8
        antenna='5' # all baselines with antenna 5
        antenna='5,6' # all baselines with antennas 5 and 6
scan -- Select data based on scan number - New, under developement
        default: '' (all); example: scan='>3'
msselect -- Optional data selection (field,spw,time,etc)
        default:'' means select all; example:msselect='FIELD_ID==0', 
        msselect='FIELD_ID IN [0,1,2]' means select fields 0,1 and 2
        msselect='FIELD_ID <= 1 means select fields 0, 1
        msselect='FIELD_ID==0 && ANTENNA1 IN [0] && ANTENNA2 IN [2:26]'
           means select field 0 and antennas 0 to 26, except antenna 1.
        Other msselect fields are: 'DATA_DESC_ID', 'SPECTRAL_WINDOW_ID',
        'POLARIZATION_ID', 'SCAN_NUMBER', 'TIME', 'UVW'
        See ccokbook for more details

niter -- Number of fitting iterations to execute
        default: 5; example: niter=20
comptype -- component model type
        default: 'P';
        Options: 'P' (point source), 'G' (elliptical gaussian),
                 'D' (elliptical disk)
sourcepar -- Starting guess for component parameters
        default: [1,0,0];  (for comptype='P')
        IF comptype = 'P' then
          sourcepar = [flux,xoff,yoff] where
            flux = Jy, xoff = arcsec-east, yoff = arcsec-north.
        IF comptype = 'G' or 'D', then
          sourcepar = [flux,xoff,yoff,majax,axrat,pos] where
            majax = arcsec, axrat < 1, pos=angle in deg
varypar -- Control which parameters to let vary in the fit
        default: [] (all vary);
        example: vary=[F,T,T]

examples:

     fit a point:
        comptype = 'P'
        sourcepar = [0.4,0.2,-0.3];
        varypar = [T,T,T]

     fit a circular Gaussian:
        comptype = 'G'
        sourcepar = [1.4,0.3,-0.2,0.3, 1, 0]
        varypar    = [ T , T ,  T , T , F, F]
            

outfile -- Optional output component list table
        default: ''; example: outfile='componentlist.cl'


How to get the output values:

    cl.open('componentlist.cl')
    fit = cl.getcompoent()             stores component information
    fit                                to see the whole mess
    flux = fit['flux']['value']        to store the I,Q,U,V, flux
    print flux

    ra = fit['shape']['direction']['m0']['value']
    dec =fit['shape']['direction']['m1']['value']
    print ra, dec

    bmaj = fit['shape']['majoraxis']['value']     to get major axis
    bmin = fit['shape']['minoraxis']['value']     to get minor axis

Definition at line 13 of file uvmodelfit.py.

References task_uvmodelfit.uvmodelfit(), and vla_uvfits_line_sf.verify.