Add Gaussian state space model distribution. #1904
Merged
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR adds a Gaussian state space model distribution which generalizes a Gaussian random walk. The state vector$\mathbf z$ evolves as $\mathbf{z}_t = \mathbf{A}\mathbf{z}_{t-1} +\boldsymbol\epsilon_t$ , where $\mathbf A$ is a square transition matrix and $\boldsymbol\epsilon_t$ is innovation noise for step $t$ . The distribution is implemented as a transformation of a multivariate normal distribution using a recursive linear transformation from #1766.