AIPS Patches

Patches to 15OCT98

This page most recently updated on $Date: 2001/12/28 20:50:45 $ (UT)

You will find patches to known bugs in 15OCT98 here.

The following is a list of pointers to the different patches in this document.

FTPGET incorrectly indicates DA00 status. 1998-11-25
Error in gridded Clean component modeling.. 1999-01-05
Error in appending to very large UV files.. 1999-01-19
Error in copying VLBI tables in FLGIT.. 1999-01-20
Revised documentation for calibration transfer. 1999-03-30

The remainder of this document is comprised of the patch descriptions pointed to by the above references.

Task:

FTPGET

Summary:

FTPGET incorrectly tells you that the TCD000000; file did not get transferred. For this release of AIPS, there is no TCD000000; file; instead there is a TCD000001; file which almost certainly did get downloaded if you allowed INSTEP1 to get the binaries for you.
A quick fix for this during the install phase is to simply interrupt INSTEP1 when it claims not everything got downloaded, and start it again. It will now think a binary version is present. If you have not yet begun INSTEP1, you can replace the FTPGET file as follows:

Files:

/15OCT98/SYSTEM/UNIX/INSTALL/FTPGET

Fix:

Fetch the file listed above and place it in the corresponding area on your system.
(Re)start INSTEP1.

Documentor:

Pat Murphy

Date:

1998-11-25

Task:

Gridded Clean-component modeling

Summary:

A bug has been found in the code which subtracts a Clean Component model from uv data using the gridded method. The term which specifies the Z separation of a field from the phase center (


sqrt (1 - xshift**2 - yshift**2)

) was supposed to be scaled by the ratio of the frequency of the first spectral (or IF) channel in the model subtraction to the reference frequency. This scaling factor was omitted from the code, apparently forever or at least since 1990. The bug can be important. In a test case, with data at declination -26, a strong interfering source 1 degree north of the phase center, and a frequency difference of 20%, the Clean in IMAGR was quickly divergent. Note that this test involves a large frequency difference, a largish separation, and a declination and direction of separation that emphasize the W * Z term. There was no error when the frequency of the first channel/IF was the reference frequency. This is usually the case in multi-IF bandwidth synthesis with BIF = 1. In spectral-line, single-channel synthesis the frequency differences are normally very small. And, at more northerly declinations or field separations with horizontal parts of the vector, the W * Z term is less important. Perhaps this is why this error was not reported and found until now.

Files:

/15OCT98/Q/SUB/NOTST/ALGSUB.FOR
/15OCT98/Q/SUB/NOTST/ALGSTB.FOR

Fix:

Fetch the files listed above and place them in the corresponding area ($QNOT) on your system.
COMRPL $QNOT/ALGSTB $QNOT/ALGSUB
COMLNK $QPGOOP/{BLING,GPHAS,IMAGR,SCMAP,WFCLN}
COMLNK $QYPGNOT/MX
COMLNK $QPGNOT/{BLCAL,BPASS,CALIB,CPASS}
COMLNK $QPGNOT/{FRING,KRING,LPCAL,PCAL}
COMLNK $QPGNOT/{UVADC,UVSUB}

Documentor:

Eric Greisen

Date:

1999-01-05

Task:

Appending to very large files

Summary:

A bug in the routine that initializes uv data I/O was found when it attempts to append to a file that is already larger than 2 Gigabytes. This only applies on HPs, DECs, and those Solaris 2.6+ systems compiled to allow such large files. UVINIT is used everywhere, but FITLD is the main place that this problem would be seen.

Files:

/15OCT98/APL/SUB/UVINIT.FOR

Fix:

Fetch the file listed above and place it in the corresponding area ($APLSUB) on your system.
COMRPL $APLSUB/UVINIT
COMLNK $APGNOT/FITLD
You may also need to COMLNK other uv tasks if they are to read large files beginning more than 2 Gigabytes from the beginning.

Documentor: