Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix parallelization problems in noise estimation #728

Merged
merged 4 commits into from
Jan 26, 2024

Conversation

keskitalo
Copy link
Member

@keskitalo keskitalo commented Jan 24, 2024

Noise estimation code struggled with observations composed of a number of short intervals, especially when lagmax was much longer than individual window.

Furthermore, the data redistribution that is used to allow arbitrary crosscorrelators to be evaluated was affecting the results.

This PR addresses both of those concerns. Furthermore, it removes the unnecessary detrending step what was redundant with the highpass filter already being applied.

Finally, noise estimation is now performed independently in each interval. Earlier, the entire observation was analyzed together with the gaps between intervals simply flagged. This way there is no risk of sample pairs spanning two intervals.

@keskitalo keskitalo requested a review from tskisner January 24, 2024 22:56
with 8 or 16 processes per group:

* When duplicating an observation, also duplicate per-detector
  flags.

* When redistributing an observation, reset per-detector flags
  before setting.

* Make the common mode removal an option (default True) prior
  to noise estimation.  This is useful if the data has already
  had the common mode removed prior to this operator.

* When high-pass filtering data that is distributed by time slices
  there may be some chunks that are fully flagged.  This should
  not be an error.  Instead, the flagged timestream is set to zero.

* When communicating overlaps, ensure that the span used (lagmax
  + half_average) is less than the number of samples.
Copy link
Member

@tskisner tskisner left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thanks for all this work. I tested the latest commit on this branch on 16 processes with realistic flagging and confirmed everything works as expected.

@keskitalo keskitalo merged commit f62013b into toast3 Jan 26, 2024
6 checks passed
@keskitalo keskitalo deleted the noise_estimation_fix branch January 26, 2024 16:08
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

2 participants