Interpolation and Sampling - chitsaw/psi GitHub Wiki

Interpolation and sampling are performed in Platform for Situated Intelligence via the corresponding Interpolate and Sample operators. These operators rely on a specified interpolator class - please first read the in-depth topic on Stream Fusion and Merging to first understand interpolators before proceeding below.

Both Interpolate and Sample take as a first parameter either a clock stream that drives the interpolation/sampling by providing the interpolation or sampling points, or a TimeSpan interval (in which case a generator stream with that cadence is produced and used).

The Interpolate operator is the most general one and accepts any interpolator.

For example:

var interpolated = doubleStream.Interpolate(TimeSpan.FromMilliseconds(100), Reproducible.Linear());

will generate an interpolated stream using linear interpolation, at a cadence of 100 milliseconds.

The Sample operators are intended for use to perform sampling, i.e. selecting a specific message from the source stream at a given cadence. The Sample operator accepts as a second parameter a RelativeTimeInterval or a TimeSpan tolerance and essentially performs sampling by interpolating with the corresponding Reproducible.Nearest interpolator. For instance:

var sampled = source.Sample(TimeSpan.FromMilliseconds(100), RelativeTimeInterval.Past());

will construct a sampled stream on 100ms cadence that contains at each sampling point the last message on the source stream.