make-space-instance

Purpose
Create a new space instance.

Package   :gbbopen

Module   :gbbopen-core

Arguments and values

Returns
The created space instance.

Events
When a space instance is created, events are signaled in the following sequence:

1. An nonlink-slot-updated-event or link-event is signaled for each slot in the newly created space instance. A link-event is also signaled for each inverse pointer from an existing space instance or unit instance to the newly created space instance.
2. An instance-added-to-space-instance-event is signaled for each space instance on which the newly created space instance is added.
3. A instance-created-event is signaled.

Errors
Use of an initialization argument that has not been declared as valid.

The supplied or generated instance name is identical to the instance name of an existing unit instance of class.

Detailed syntax

The default ordered-comparison-type, if unspecified, is number. The default enumerated-comparison-type, if unspecified, is eql. The default boolean-comparison-type is t.

Terms

Description
Specifying a :space-instances initialization argument causes that value to be used instead of any :initial-space-instances specification associated with the space class. However, note that placing a space instance on other space instances is unrelated to the layout of blackboard repository hierarchy, which is specified by the :paths initialization argument. Placing a space instance on other space instances is no different from placing any other unit instance on a space instance.

See also
    allowed-unit-classes-of
    change-space-instance
    children-of
    define-space-class
    delete-all-space-instances
    delete-space-instance
    describe-instance
    describe-space-instance
    describe-space-instance-storage
    dimensions-of
    make-instance
    parent-of

Examples
Create a top-level space instance, bb, that cannot store any unit instances:

  > (make-space-instance '(bb) 
       :allowed-unit-classes nil)
  #<standard-space-instance (bb)>
  > 

  > (make-space-instance '(bb hyps)
       :dimensions (dimensions-of 'hyp)
       :allowed-unit-classes '((hyp :plus-subclasses))
       :storage '(((hyp :plus-subclasses) (x y) 
                   uniform-buckets :layout ((0 10000 100)
                                            (0 10000 100)))))
  #<standard-space-instance (bb hyps)>
  >

Here is an improved space instance for hyp unit instances named hyps, with both uniform-bucket storage for indexing in the x and y dimensions and hashed storage to retrieve match candidates via classification dimension values:

  > (make-space-instance '(bb hyps)
       :dimensions (dimensions-of 'hyp)
       :allowed-unit-classes '((hyp :plus-subclasses))
       :storage '(((hyp :plus-subclasses) (x y) 
                   uniform-buckets :layout ((0 10000 100)
                                            (0 10000 100)))
                  ((hyp :plus-subclasses) (classification) 
                   hashed)))
  #<standard-space-instance (bb hyps)>
  >

Note
The make-space-instance function is equivalent to using make-instance with the desired space class and with the initialization argument :instance-name containing the space-instance path. However, using make-space-instance provides a convenient shorthand and is preferable stylistically.

make-space-instance