[defrost]

Cutting to the chase, does this make the summary results available in the midst of the sequence; eg: if it takes two hours to gather pressure data (or any other time series data) does this expose the running variance 10 minutes in, an hour in, etc. ?

[kenko]

Not currently, but it would certainly be possible to add something like that---exposing the running stats for partial subsequences of the input sequence would just be a matter of replacing the "reduce" in the definition of calculate with "reductions" (well, and at least one other change, but at a similar level of complexity). That wouldn't give you ten, sixty, etc. minutes in to the data gathering, because it wouldn't be tied to how long the actual computation of the elements of the input seq---something outside calculate's purview, ATM---was taking, but it would start delivering running answers right away.

[defrost]

Running answers right away is fairly useful; a bit of a challenge in that problem domain is with multichannel sensors ("cameras" with multiple frequency bands, satellites like MODIS, radiometric spectrometers, etc.) where the sharpest "image" is produced by using an SVD (singular value decomposition) type transform to reduce (say) 256 input channels to (say) 6 major dimensions and using those to recreate an enhanced image. Producing branchless code to generate basic running stats (min, mean, max, variance, trends) on multiple input channels is a bit of puzzle, generating an efficient rolling SVD enhancement (best image based on most recent observations) is a bit trickier.

The application areas are continuous processing of continuously arriving data, infinite unbounded sequences.