[daip] FRING in TST, bug fix 13398 has no effect

Thu Sep 15 05:07:14 EDT 2011

Hi

I did some more test using FRING in version 'new' and 'tst' using ap9=1.

The SN-tables produced by both versions are identical. The bug fix
mentioned in CHANGE.DOC (13398.  January 21, 2011) seems to
have no affect in our TST version (31DEC11). 

Can you please check, if the correct version of FRING is implemented under TST.

best regards 
                              Thomas

here a more extreme example:

  1    2   14-SEP-2011  20:26:37     FRING     Time=   0/ 19 05 29, Polarization = 2

   1    3   14-SEP-2011  20:26:59     FRING     Ant(01): Phas=****** rate=      6.69 delay=    347.87 SNR=  10.3
   1    3   14-SEP-2011  20:26:59     FRING     Ant(02): Phas=****** rate=    -42.26 delay=    196.57 SNR=   7.8
   1    3   14-SEP-2011  20:26:59     FRING     Ant(03): Phas=****** rate=    -24.21 delay=    367.99 SNR=  10.7
   1    3   14-SEP-2011  20:26:59     FRING     Ant(04): Phas=3271.6 rate=    -75.26 delay=   -211.49 SNR=  12.0
   1    3   14-SEP-2011  20:26:59     FRING     Ant(06): Phas=****** rate=   -112.27 delay=    312.61 SNR=   9.6
   1    3   14-SEP-2011  20:26:59     FRING     Ant(07): Phas=****** rate=    -26.83 delay=    342.43 SNR=   6.4
   1    3   14-SEP-2011  20:26:59     FRING     Ant(08): Phas=-670.8 rate=    -24.45 delay=    146.65 SNR=   9.2
   1    3   14-SEP-2011  20:26:59     FRING     Ant(09): Phas=****** rate=    -33.23 delay=    134.15 SNR=   7.7
   1    3   14-SEP-2011  20:26:59     FRING     Ant(10): Phas=-720.6 rate=     -5.82 delay=    295.55 SNR=   8.1
   1    3   14-SEP-2011  20:26:59     FRING     Ant(11): Phas=****** rate=    -24.56 delay=    190.89 SNR=   7.8
   1    3   14-SEP-2011  20:26:59     FRING     Ant(12): Phas=****** rate=     -2.80 delay=    311.55 SNR=  10.4
   1    3   14-SEP-2011  20:26:59     FRING     Ant(13): Phas=-342.8 rate=    -40.83 delay=    189.65 SNR=   7.8

----------  Forwarded Message  ----------

Subject: Fringe, exhaustive baseline search gives wrong solution
Date: Wednesday 14 September 2011
From: Thomas Krichbaum <tkrichbaum at mpifr-bonn.mpg.de>
To: "aips, daip" <daip at nrao.edu>

Hi,

I use FRING in version 'new' and 'tst'. I run it in the exhaustive baseline search mode using ap5=1 and ap7=1. 
This is necessary since the data have low SNR (3mm-VLBI). 

The parms are set like this:
REFANT        5   
SEARCH       12   11 3 4 13 2 0
SOLINT          4
SOLSUB        2
SOLMIN         1
APARM 2 0 0 0 1 2 4 0 1 0 
DPARM 2 500 500 1 0 0 1 0

As in some earlier versions, I again encounter 'wrong' solutions, which appear occassionally.
I thought that bug was fixed some time ago. 

In the coarse search I see phases above 360 deg or even with "****". 

The POSSM plot shows that the delays on some baselines come out wrongly. 

When I switch off exhaustive mode (set aparm9=0) the effect seems to dissappear. However
that mode gives too few solutions, since FRINGE does not cycle through the full antenna list.

Here the prtmsg output for a particular scan:

   1    3   14-SEP-2011  19:12:29     FRING     IF number =    1 Poln. =   1
   1    3   14-SEP-2011  19:12:29     FRING     Fitted phases, rates, delays and SNR: [ P = phase(deg),
   1    3   14-SEP-2011  19:12:29     FRING       R = rate(mHz), D = Single-Band Delay(nsec), S = SNR ]
   1    3   14-SEP-2011  19:12:29     FRING       R = rate(mHz), D = Single-Band Delay(nsec), S = SNR ]
   1    3   14-SEP-2011  19:12:29     FRING     Ant(01): Phas=-959.6 rate=     -1.81 delay=      2.86 SNR=  20.4
   1    3   14-SEP-2011  19:12:29     FRING     Ant(03): Phas=****** rate=     27.16 delay=    -11.47 SNR=  21.6
   1    3   14-SEP-2011  19:12:29     FRING     Ant(04): Phas=****** rate=      0.74 delay=      3.06 SNR=  21.4
   1    3   14-SEP-2011  19:12:29     FRING     Ant(07): Phas=****** rate=     17.50 delay=      2.02 SNR=  20.2
   1    3   14-SEP-2011  19:12:29     FRING     Ant(08): Phas=-958.2 rate=    -24.19 delay=     -0.23 SNR=  18.6
   1    3   14-SEP-2011  19:12:29     FRING     Ant(10): Phas=****** rate=     -2.38 delay=      1.83 SNR=  21.5
   1    3   14-SEP-2011  19:12:29     FRING     Ant(11): Phas=****** rate=      2.69 delay=      2.66 SNR=  22.1
   1    3   14-SEP-2011  19:12:29     FRING     Ant(12): Phas=****** rate=     -4.39 delay=      3.46 SNR=  22.1
   1    3   14-SEP-2011  19:12:29     FRING     Standard RMS errors (deg, mHz, nsec):

Is this a bug ?

best regards, Thomas

-- 
Thomas P. Krichbaum                       
Max-Planck-Institut für Radioastronomie 
Auf dem Hügel 69                        
D-53121 Bonn / Germany

Tel. :  (Germany +49)-228-525-295
Fax :  (Germany +49)-228-525-229
e-mail: tkrichbaum at mpifr-bonn.mpg.de
URL:   http://www.mpifr-bonn.mpg.de/staff/tkrichbaum

-------------------------------------------------------

-- 
Thomas P. Krichbaum                       
Max-Planck-Institut für Radioastronomie 
Auf dem Hügel 69                        
D-53121 Bonn / Germany

Tel. :  (Germany +49)-228-525-295
Fax :  (Germany +49)-228-525-229
e-mail: tkrichbaum at mpifr-bonn.mpg.de
URL:   http://www.mpifr-bonn.mpg.de/staff/tkrichbaum