Hiperspace 2.2.1

• net8.0

  • Microsoft.Bcl.HashCode (>= 6.0.0)
  • protobuf-net.Core (>= 3.2.52)
  • System.Numerics.Tensors (>= 9.0.4)

• net9.0

  • Microsoft.Bcl.HashCode (>= 6.0.0)
  • protobuf-net.Core (>= 3.2.52)
  • System.Numerics.Tensors (>= 9.0.4)

https://www.cepheis.com/hiperspace/20250414
# Overview
This release extends the `Hipperspace` model to better support streaming aggregation of Cube and viewing of aggregates part of graph view.  It also updated `SessionSpace` to use stream replication rather than Zip file compression.

## Cube aggregation
Traditional [OLAP Cubes](https://en.wikipedia.org/wiki/OLAP_cube) do not include the notion of history unless includes as a dimension in the cube, and are either calculated
1.  *Multidimensional* cubes recalculated each night
2.  *Relational* cubes are translated into the SQL queries that aggregate at a point in time from source data
3.  *Hybrid* cubes combine an overnight batch with intraday *relational* updates

Hiperspace includes history for element stored in `Hiperspace` with access to the full history of the element.  Cube data is not overwritten whenever a value is changed intraday, but a new version is created.  This allows a point-in-time view of a `SubSpace` to be opened, or history to be used for regression analysis over time (*A portfolio/book view can be aggregated in a cube and trend-line examined as the data changes*).  Traditionally the value of the latest summary (e.g. total-sales per product) is discounted by the frequency it is examined (*you wouldn't want to calculate a per-minute summary for a product if you only analyze it once a day*) and the cost of recalculating it each night if only reviewed at month end.  

When you add the capability for regression analysis, the value of each observation increases: we presume that historical values will be re-used many times, and calculate the projection for fast access to data.

### Stream aggregation
`Hiperspace` uses Delta indexes to fast access to changes within a short epoch, and version history to calculate the delta from the last epoch.  The a price change to APPL.N stock will only update the portfolio that reference this stock, and not require the reaggregation of the entire portfolio (if APPL.N changes from $300 to $290 for a portfolio of 100 shares, the value of the portfolio changes by $-900, which is added to the current portfolio value) . Point-in-time `AsAt` views of the `SubSpace` are used to perform aggregation *concurrently* with other changes (*which will be included in the next epoch calculation*) without degradation to performance.

### code changes
Additional interfaces are added for runtime access to Cube data:
* **CubeDimension** property of a {`entity`, `segment`, `aspect`} now includes an `ICubeDimension` interface that includes the *CubeSlice* string (used to directly access the summary value for a cube node, without retriveing intersection with other dimensions
* **CubeHierarchy** property to indicate that the dimension is part of a hierarchy and aggregates for levels in the hierarchy should be calculated in addition to the leaf values
* **CubeFact** property of of a {`entity`, `segment`, `aspect`} now includes `ICubeFact` for the fact table, and includes methods to add dimensions and retrieve values generically.

These methods enable cube data to be viewed as part of graph view.  When a *Cube Dimension* is a graph node, a `Node` view is added *fact table* with two edges *Dimension*-(Fact)->*Fact* for traversal from dimennsion to fact, and *Fact*-(Dimension)->*Dimension* for traversal from Fact to the Dimension.

For example, a Cube of Transactions with dimensions {Customer, Product, Region}, the addition of *Fact Nodes* creates transitive edges for {Customer->Product, Customer->Region, Product->Region} via transaction fact.  When combined with *Transitive Edges* (*Hyper Edges*) it becomes possible to view to Cube data through a graph view in a [Hypergraph](https://en.wikipedia.org/wiki/Hypergraph).

For the Customer "British Steel" (*Client Node*), and "Coking Coal" (*Product Node*) the Quantity Fact contains the total available ( "British Steel" -> "Coking Coal" -> Quantity Edge), and ( "British Steel" -> "Coking Coal" -> "Scunthorpe" -> Quantity Edge) references only the total currently in that region.

[image]Sites/hiperspace/cube-edge.png[/image]

## Transitative Edge becomes Hiper Edge
The name of `SetSpace` `TransitiveEdge` has been changed to `HiperEdge` better distinguish Graph Edges that are transitively projected as Hiper-edges, from edges that might themselves be transitive without being projected.  This **breaking change** is used because Hiper-Edges can be viewed as *Cube edges* where each step in a *Cube Edge* is also a drill-down into the dimensions of a **Cube** for the dimensions in the hipergraph.  

`HiperEdge` is used instead of the mathematically correct *hyper-edge* (within a [Hyper-Graph](https://en.wikipedia.org/wiki/Hypergraph) because our implementation explicitly includes the references to the *Hiper Edge* (extended) and *Edge* (projected): The inclusion of the path enables the identification of each *Dimension* and `CubeSlice` referenced

## Hiperspace.DB
`Hiperspace.DB` provides functionality to project *Edge* to *HiperEdge*, and aggregate *Fact Cubes* close to the data without network access - especially important for web-assembly clients that may be accessing the `Hiperspace` over the internet.
*Edges*, *HiperEdges* and *Facts* can be used in SQL queries (our implementation of SQL allows joins to nested sets (syntax appears as a cross-join since the actual join is created by ownership).
```
select  p.Name as Person,
       r.To.Name as Relation,
       r.TypeName as Relationship,
       r.Length as Length,
       r.Width as Width
from    Persons as p,
       p.AllRelatives as r
where   p.Name = :name;
```
## SessionSpace
`HiperSpace` has additional streaming methods for `ExportAsync` and `ImportAsync` for bulk data import, but also for `SessionSpace` which might exceed message sizes when saving a large amount of data over the internet.  The legacy `Space()` function has is now `[Obsolete]`, and will be removed in a future release

## Hilang
The Hilang AOT compiler has been updated to provide the implementation for the `ICubeDimension` and 'ICubeFact` views.