From gtaylor@cv3.cv.nrao.edu Wed Oct 17 17:14:15 2001 Date: Wed, 17 Oct 2001 16:59:01 -0600 (MDT) From: gtaylor To: aips2-naug@zia.aoc.NRAO.EDU Cc: Greg Taylor Subject: aips++ testing log of Oct 17 Testing AIPS++ Detailed Log Oct 17, 2001, session: Started up testing to try out the new and improved msplot. Working on AT166 data in daily 1.6 Build 329. Fired up the msplot tool from the tool manager. Don't forget to set Edit=T. After Ralph reminded me to unset the fields entry in data selection and select only the first of the two spectral windows (IFs), I was able to load and recognize my data set. Note that the data is rotated by 90 degrees and mirror-imaged compared to what is shown in TVFLG. Antenna numbers go up the Y axis starting from 1, while time increases to the right. To find out about a pixel place the cursor over it. The Y axis value will appear as something like 6022. This decodes to baseline 6 with 22. The formula is Y=antenna1*1000 + antenna2. Ralph is working on a little widget to make it easier to decode the output from the viewer. One problem that we noticed right away was that antennas that were out at the beginning of the run get dropped for the entirety, even if they come back in later. This was bugged by Ralph: Bug: AIPS++ defect AOCso02253: Request gridding different data And we think this same defect was also causing aips++ to crash (abnormal child termination). But it was still possible for me to call up msplot from glish. Which is what the remainder of this e-mail is based on. Another problem immediately obvious was that the startup of msplot is a bit slow, about 2 minutes for a standard VLA continuum observation lasting about 1.8 hours (212000 visibilities). About 50 seconds is spent copying the flag table to enable the user to revert to a previous flagging if so desired. Ralph says it takes so long to copy this table because it goes through glish. He is thinking about ways to optimize it. We also noticed a lot of error messages being directed to the glish interface. Ralph will be turning some of these off. Others will probably stick around. Getting back to the data, the zoom feature works nicely. Sufficient instructions on using it appear in the popup help after the mouse has hovered over the magnifying glass icon on the left panel of the viewer long enough. Switching between correlations (LL, LR, RL, RR) is also quite easy using the controls on the right panel. A feature quite notable in its absence is the ability to display the rms of amplitude, or an amplitude difference. The only display options are amplitude and phase. Time averaging doesn't appear to be an option either so it will be interesting to see what happens when something more substantial than this little test data set is loaded. Still it is possible to identify and flag bad data. Using the zoom feature is fairly essential. Here are a few things that one might want to do in order roughly of popularity: * flag antenna for a single time: Zoom in on the antenna. Then use the cross hairs button (3rd from bottom on the left panel) to point it at any one pixel of the bad baselines to this antenna. Be sure that the "antennas" button on the top of the viewer is activated. Then double click within the cross hairs (good aim is assumed). Once you double click you'll see a message in the log file "Defined editting command 1". But thats it. Nothing actually gets flagged until you click on the green flag button in the viewer. Since it can take a minute or so to flag and redisplay the data, it is probably a good idea to perform a few edits and then actually command them flagged. Sometime the viewer won't let you move the cross hairs. In this case hit the "Esc" key and it will get rid of the old cross hairs. Then define a new one. You can only have one at a time. * flag antenna for a duration: define a rectangle across the time range and including some of the bad baselines. Be sure that the "antennas" button is activated. Then double click inside the rectangle to define a new edit. * flag region: define a rectangle and double click inside it. * flag baseline: aim a crosshair at a visibility and double click inside it. Don't forget to make sure that the antennas button is NOT activated. Interactive clipping of high visibilities is another useful feature that is currently missing in action. The scope of the edits can be modified using the buttons on the viewer. This covers what is needed, but there is a minor bug that prevents all correlations from being flagged. Ralph is working on this and I think the fix will be in tomorrow's "daily". In the next couple days I plan to continue testing of msplot to verify some of the fixes that Ralph made today, and to check on some 1 pixel type offsets that I'm seeing. More later. --- end of testing. Frustration meter reads: |**** | low high