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calibrater.setsolvebandpoly  Function
2.1.1 Specialization of setsolve for polynomial B (bandpass) solving
Description
This function is a specialization of the setsolve method which should be used
to arrange for bandpass solving when polynomial solutions for B are desired,
e.g., when perchannel SNR on calibrators is too low to obtain a useful
sampled bandpass.
Prior to the solution, the visibility data are averaged in time, and the solution is performed for both phase and amplitude.
This method uses most of the same parameters as the generic setsolve, with a few unique additions:
 degamp and degphase
 The parameters permit specification of the polynomial order to use in amp and phase. Specifying 0 (zero) yields constant solutions.
 visnorm
 This parameter is used to normalize the assembled spectral data, in a per baseline manner. If set True, this will have the effect of removing any nonfrequencydependent closure errors (e.g., as caused by source structure, or introduced by the instrument) from the data, and should be used with caution. The resulting solutions will be effectively normalized as well. When visnorm=F is used, closure errors in the data (as supplied to the solver) may be visible in the form of offsets between the data and solutions. For bandpass calibration, this is usually ok, as the shape of the bandpass is the most important aspect of the solution. In future this parameter will be generalized and made available for other solve types. (NB: Use of solnorm=True still provides for postsolve normalization of the solutions.)
 maskcenter and maskedge
 These parameters control how many channels are ignored onthefly, at the center and edges of each input spectral window, respectively. To avoid edge channels, it is almost always better to flag these channels directly, or select against them in setdata. Aggressive use of maskedge (large values), will yield polynomial solutions which will tend to diverge at the edges (especially when the polynomial degree is also high), because maskedge does not change the frequency domain of the solutions. Such solutions should be used with caution in subsequent operations. (It is best to avoid use of maskedge.)
The BPOLY solution is performed for both phase and amplitude, and the result will be stored in the same table. The frequency domain of the solutions is limited to only the range of frequencies selected in selectvis. When correcting data with these solutions (for other solves or with correct), only data within this domain will be corrected. Data outside (e.g., edge channels avoided in setdata for the solve), will not be corrected. Therefore, the same (or narrower) channel selection is recommended for all operations using solutions produced by this function and solve().
Note that the combine parmaeter can be used meaningfully with the BPOLY solver. When combine=’spw’, the data from multiple spws will be combined on a common frequency axis, and a single polynomial will be determined spanning them all. This is different than for ordinary sampled ’B’ solutions, for which combine=’spw’ causes the bandpass to be combined on a common channel axis, effectively yielding a mean bandpass for the set of spws.
Arguments
Inputs 
 
table 
 Output calibration table name
 
 allowed:  string 

 Default: 
 
append 
 Append to existing table?
 
 allowed:  bool  
 Default:  false 

t 
 Solution interval (units optional)
 
 allowed:  any 

 Default:  variant


combine 
 Data axes on which to combine solving (scan, spw,
and/or field)
 
 allowed:  string 

 Default: 
 
degamp 
 Polynomial degree for amplitude solution
 
 allowed:  int  
 Default:  3 

degphase 
 Polynomial degree for phase solution
 
 allowed:  int 

 Default:  3 

visnorm 
 Normalize data prior to solution
 
 allowed:  bool 

 Default:  false 

solnorm 
 Normalize result?
 
 allowed:  bool 

 Default:  true 

maskcenter 
 Number of channels to avoid in center of each band
 
 allowed:  int 

 Default:  0 

maskedge 
 Fraction of channels to avoid at each band edge (in %)
 
 allowed:  double 

 Default:  5.0 

refant 
 Reference antenna
 
 allowed:  any 

 Default:  variant


bool
Example
cb.open(’ngc5921.ms’);
cb.selectvis(field=’1331*’)
cb.setsolvebandpoly(table=’bpoly’,degamp=5,degphase=7);
cb.solve();
cb.close();
In this example, amplitude (degree 5) and phase (degree 7) Chebychev
polynomial bandpasses are determined using the default parameters.
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