; VBGLU ;--------------------------------------------------------------- ;! Glues together data from multiple passes thru the VLBA corr. ;# Task UV SPECTRAL VLBI ;----------------------------------------------------------------------- ;; Copyright (C) 1995, 2006-2007 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- VBGLU LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC VBGLU Task which glues uv frequency blocks back together INNAME Input UV file name (name) INCLASS Input UV file name (class) INSEQ 0.0 9999.0 Input UV file name (seq. #) INDISK 0.0 9.0 Input UV file disk unit # IN2NAME Second UV file name (name) IN2CLASS Second UV file name (class) IN2SEQ 0.0 9999.0 Second UV file name (seq. #) IN2DISK 0.0 9.0 Second UV file disk unit # IN3NAME Third UV file name (name) IN3CLASS Third UV file name (class) IN3SEQ 0.0 9999.0 Third UV file name (seq. #) IN3DISK 0.0 9.0 Third UV file disk unit # IN4NAME Fourth UV file name (name) IN4CLASS Fourth UV file name (class) IN4SEQ 0.0 9999.0 Fourth UV file name (seq. #) IN4DISK 0.0 9.0 Fourth UV file disk unit # OUTNAME Output UV file name (name) OUTCLASS Output UV file name (class) OUTSEQ -1.0 9999.0 Output UV file name (seq. #) OUTDISK 0.0 9.0 Output UV file disk unit #. ---------------------------------------------------------------- VBGLU Task: This task is designed to deal with VLBA data that have been correlated in multiple passes. Multiple passes in the VLBA sense do not have the historical connotation associated with older VLBI correlators. For the VLBA, all baselines are correlated simultaneously but only 8 IFs can be correlated at any one time. So the data have to be glued together in the spectral domain. Up to 4 input files can be handled simultaneously - this will deal with the worst case scenario (MkIII Mode A). The task has been rewritten so no data are lost even when not all files have data from the same times. Adverbs: INNAME.....Input UV file name (name). Standard defaults. INCLASS....Input UV file name (class). Standard defaults. INSEQ......Input UV file name (seq. #). 0 => highest. INDISK.....Disk drive # of input UV file. 0 => any. IN2NAME....Second file name. IN2CLASS...Second file class IN2SEQ.....Second file sequence number. IN2DISK....Second file sequence number. IN3NAME....Third file name. IN3CLASS...Third file class IN3SEQ.....Third file sequence number. IN3DISK....Third file sequence number. IN4NAME....Fourth file name. IN4CLASS...Fourth file class IN4SEQ.....Fourth file sequence number. IN4DISK....Fourth file sequence number. OUTNAME....Output UV file name (name). Standard defaults. OUTCLASS...Output UV file name (class). Standard defaults. OUTSEQ.....Output UV file name (seq. #). 0 => highest unique OUTDISK....Disk drive # of output UV file. 0 => highest with space for the file. ---------------------------------------------------------------- VBGLU Glues VLBA data together IF by IF. DOCUMENTOR: P.J.Diamond & Amy Mioduszewski PURPOSE NOTE: VBGLU will only work on single FREQID datasets. VBGLU Glues together data that were correlated in multiple passes on the VLBA correlator, multiple pass is not used in its historical sense of different baselines/pass but in the sense of different IFs/pass. This is necessary because the VLBA correlator can only deal with 8 IFs at a time, but when MkIII Mode A,B or C are correlated the data have to be split up in frequency space. VBGLU reads the file headers and FQ tables and constructs a composite header/FQ table. It reads all input files constructing a time-ordered list of output records. When times and baselines match the output data will contain the input data from all input files. For times when the files do not match, some output IFs will be marked as flagged while the other output IFs will contain the appropriate data. No data will be lost in this way, although some records may not contain data for all IFs. The task is more efficient if the data are in strict time-baseline order, but any order can be processed. Several assumptions are implicit in this process: (1) The source/antenna numbers are identical - use task MATCH to fix this if needed. (2) There are the same number of spectral channels per IF (3) There is a sigle FREQID VBGLU then copies those tables that have no IF dependency. It then takes the tables that do have arrays that depend on IF and performs an analogous operation to that done on the uv-data. The tables from the first file are taken to be the master representations and the others are merged with them. The tables that are bonded in this way are: AT IM CL SN MC TY PC BP BL SU GC CQ If there is a significant mismatch between the tables a warning message is issued. CT Table -------- One table that is treated differently than those above is the CT table. The CT table is the CALC table and contains the earth orientation parameters (EOPs) that were used by the correlator. It is possible that the EOPs used were not the most accurate because it takes a week or two after the observation date to get the most accurate EOPs (see VLBA Test Memo 69). Inaccurate EOPs can substantially negatively effect phase referencing experiments. Therefor it is recommended that they are corrected with CLCOR (OPCODE=EOPS; see EXPLAIN CLCOR). CLCOR uses the CT table to calculate the difference between the old EOPs and the new EOPS. Therefor, it is VITAL that the CT table be correct. The CT table has no IF dependence but it is possible in the two correlation that the EOPs were different. So VBGLU compares the CT tables and if they are identical and if they are not it refuses to copy them and issues a message. If VBGLU refuses to copy the CT table to the output file and you want to fix the EOPs for your experiment you can follow these steps, BEFORE running VBGLU: 1) run CLCOR (OPCODE='EOPS') on both files. 2) run SPLAT to apply those corrections (because VBGLU only copies the first CL table). 3) run VBGLU on the SPLATed files