[evla-sw-discuss] Simple subarrays: a modest proposal

[Michael Rupen]

On Wed, 2 Apr 2014, Ken Sowinski wrote:

> On Tue, 1 Apr 2014, Vrcic, Sonja wrote:
>
>>  Hi Michael, it just occurred to me that there is one more possible
>>  solution: vci parameter "mapping time" could be used to delay the mapping
>>  of subarrays until all are received by CM.
>>
>>  Parameter mappingTime has been implemented to allow messages transmitted
>>  from different sources to be mapped as a single configuration, and to
>>  provide deterministic mapping in general. Mapping time has not been used
>>  so far, but I tested it long ago and to my knowledge it works.
>>
>>  Executor could transmit Activation Trigger for each subarray, as it does
>>  now, and use different Activation ID for each, as it does now;  the only
>>  change would be to add a parameter mappingTime to the Activation Triggers
>>  to postpone the mapping of vci messages until all subarrays that should
>>  start at the same time are received by CM. The necessary delay could be
>>  determined empirically (by testing). Also, the Executor would have to be
>>  aware that subarrays (Scheduling Blocks) belong to the same observation
>>  (and should be mapped at the same time). If that is not already the case,
>>  perhaps an indication (a parameter 'delayMapping') could be passed to it,
>>  to let it know. This would still require changes in the Executor, but
>>  perhaps smaller. Sonja
>
> The better approach might be to include this in the .vci files
> generatd by m2s.  Knowledge of subarrays and their interrelations
> exists (or will exist) there (or in OPT), but does not in the executor.

This is a good thought, but is probably too much for the sort of quick &
dirty initial implementation I'm thinking of.  I _would_ like to try some of
these possibilities as tests though, to see whether they fix our problems.
If the use of activation triggers works that could be really sweet...

        Michael