[daip] some questions on AP size, AIPSMARK

[Lynn D. Matthews]

Our AIPS managers have been doing some testing on how AP size affects AIPS
performance, and have found that there seems to be a sharp peak in
efficiency when the AP size is set to 20 MW (compiled value was 81 MW).
They are discussing whether this should therefore be made the default for
our AIPS systems. Before they do this, I have a few questions.

Could you explain why performance should drop precipitously if the AP size
is maximized? Or is it likely to be a function of some additional factors?

I find that if I try to image a 8192 image with a 4096 beam using a 20MW
AP (something I need to do a lot of), IMAGR tells me: "only 637 rows
in 5120k AP". I assume this means that in my case I am being slowed down
by the limited AP size?

Finally, what is the role of the AIPSMARK parameter in SETPAR---i.e., does
changing this value affect performance?


Thanks,

Lynn Matthews