blflag: Too many points

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Erik.Kool
Posts: 4
Joined: Thu Dec 03, 2015 11:08 am

blflag: Too many points

Post by Erik.Kool »

First time user here, so apologies if this is a trivial problem. I'm running miriad on a macbook, I have successfully gone through the Basic continuum data reduction guide with no errors, so I assume everything is in working order.

However, I'm currently trying to reduce a recent data set and when running the blflag task (on 1934-638), I get the fatal error message "Too many points". So the task runs fine on the dataset of the guide (CX208, visdata = 30MB), but not on my own (C1473.5500, 2015-11-21, visdata = 110MB):


blflag% blflag vis=1934-638.5500 device=/xs stokes=xx,yy axis=chan,amp options=nofqav,nobase

blflag: Revision 1.21, 2014/07/18 02:45:48 UTC

Applying bandpass corrections to 1934-638.5500
Applying gain corrections to 1934-638.5500
Reading the data...
### Fatal Error: Too many points!


I tried select="increment(2)", but that produced "### Fatal Error: No visibility data found".


My specs (it's quite an old machine):
Processor: 2.4 GHz Intel Core 2 Duo
Memory: 4 GB 1067 MHz DDR3
OS: OS X 10.9.5


Thanks,
Erik
Mark.Wieringa
ATCA Expert
Posts: 297
Joined: Mon Feb 08, 2010 1:37 pm

Re: blflag: Too many points

Post by Mark.Wieringa »

Hi Erik, and welcome to the forum,

if you look at the help for blflag you may notice a hint under yrange that avoids this problem:

" For amplitude type plots you can greatly reduce the
number of points to plot by using something like yrange=0.3 to
cut out noise."

Try this and see how you go,

Cheers,

Mark
Erik.Kool
Posts: 4
Joined: Thu Dec 03, 2015 11:08 am

Re: blflag: Too many points

Post by Erik.Kool »

Thanks for the quick reply. Unfortunately this does not seem to work, I get the same error.
Mark.Wieringa
ATCA Expert
Posts: 297
Joined: Mon Feb 08, 2010 1:37 pm

Re: blflag: Too many points

Post by Mark.Wieringa »

Hi Erik,

Right, I just noticed you're looking at a calibrator, so the yrange trick may not work because all the amplitudes are high.
You can try looking at a single baseline at a time (don't set options=nobase) and if you still have problems, reduce the time range.

Cheers,

Mark
Erik.Kool
Posts: 4
Joined: Thu Dec 03, 2015 11:08 am

Re: blflag: Too many points

Post by Erik.Kool »

Hi Mark,

Looking at single baselines didn't help, but select a time range did. We have 12 minutes of exposure of the primary calibrator at the start, so I started with 4 minutes. That worked, as well as the whole 12 minutes. The 12 minutes at the end also got processed correctly when specifying its time range. It just does not work when you look at the whole range, oddly enough. Any idea why this would be the case? Hopefully the rest of the data set does not give rise to this problem, because doing that by hand is not doable.

Erik
Erik.Kool
Posts: 4
Joined: Thu Dec 03, 2015 11:08 am

Re: blflag: Too many points

Post by Erik.Kool »

I ran into the same problem with the secondary calibrator. I "fixed" it by doing one hour at the time, which was the limit I could do for one time block. This is not ideal, could this issue be a result from using an older machine perhaps?

Erik
Mark.Wieringa
ATCA Expert
Posts: 297
Joined: Mon Feb 08, 2010 1:37 pm

Re: blflag: Too many points

Post by Mark.Wieringa »

Hi Erik,

the number of points on the Mac version was limited to about one million. I've now increased it to 64 million, which is what it already was on 64 bit linux.
If you have an atnf account you should be able to type mirsync to get the updated blflag version.

Cheers,

Mark
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