[daip] New Ticket - [!MXR-193922]: asymmetry in gethead puthead

[Jan Wagner]

New Ticket: asymmetry in gethead puthead

Hi, in an attempt to modify the UV data headers, this seems to be a bug or shortcoming in the gethead, puthead pair (AIPS 31DEC11). Not all values of gethead are available in puthead.

> explain gethead
GCOUNT  '     Number of "groups" (real*8, UV data only)
                  this is the number of visibilities.
'PCOUNT  '     Number of random parameters (integer, UV data only)
'NAXIS   '     Number of axes (integer)
'NAXIS1  ','NAXIS2  ','NAXIS3  ','NAXIS4  ','NAXIS5  ',
'NAXIS6  ','NAXIS7  '     Number of points on axis n (integer)

> explain puthead
(none of the above exist)

> getn 97; keyword 'naxis4'; gethead; outputs gethead
AIPS 1: KEYVALUE      3           0  

> getn 97; keyword 'naxis4'; keyvalue=4; keytype='r'; puthead;
AIPS 1: KEYWORD ='NAXIS4  ' NOT RECOGNIZED

> getn 97; keyword 'if'; keyvalue=4; keytype='r'; puthead;
AIPS 1: Got(1)   disk= 1  user=1001   type=UV   B227AP.UVDATA.1

> imh
AIPS 1: Maximum version number of extension files of type FG is   1
AIPS 1: Maximum version number of extension files of type PL is  45
AIPS 1: Keyword = 'OLDRFQ  '  value =  2.19437200D+10
AIPS 1: Keyword = 'SUBARRAY'  value =            1
AIPS 1: Keyword = 'IF      '  value =  4.000000E+00

So puthead fails to modify naxis4 and the alternative approach to set 'IF' simply adds a new keyword instead of modifying the IF value (naxis4).

 - Jan


Ticket Details
===================
Ticket ID: MXR-193922
Department: AIPS Data Processing
Priority: Default
Status: Open
Link:  https://help.nrao.edu/staff/index.php?_m=tickets&_a=viewticket&ticketid=1353