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DelayedOp objects

DelayedOp-class.Rd

NOTE: This man page is about DelayedArray internals and is provided for developers and advanced users only.

In a DelayedArray object, the delayed operations are stored as a tree where the leaves are operands and the nodes are the operations. Each node in the tree is a DelayedOp derivative representing a particular delayed operation.

DelayedOp is a virtual class with 8 concrete subclasses. Each subclass provides a formal representation for a particular kind of delayed operation.

Usage

is_noop(x)

Arguments

x

A DelayedSubset, DelayedAperm, or DelayedSetDimnames object.

Details

8 types of nodes are currently supported. Each type is a DelayedOp subclass:

  Node type                        Represented operation
  ------------------------------------------------------------------
  DelayedOp (VIRTUAL)
  ------------------------------------------------------------------
  * DelayedUnaryOp (VIRTUAL)
    o DelayedSubset                Multi-dimensional single bracket
                                   subsetting.
    o DelayedAperm                 Extended aperm() (can drop and/or
                                   add ineffective dimensions).
    o DelayedUnaryIsoOp (VIRTUAL)  Unary op that preserves the
                                   geometry.
      - DelayedUnaryIsoOpStack     Simple ops stacked together.
      - DelayedUnaryIsoOpWithArgs  One op with vector-like arguments
                                   along the dimensions of the input.
      - DelayedSubassign           Multi-dimensional single bracket
                                   subassignment.
      - DelayedSetDimnames         Set/replace the dimnames.
  ------------------------------------------------------------------
  * DelayedNaryOp (VIRTUAL)
    o DelayedNaryIsoOp             N-ary op that preserves the
                                   geometry.
    o DelayedAbind                 abind()
  ------------------------------------------------------------------

All DelayedOp objects must comply with the seed contract i.e. they must support dim(), dimnames(), and extract_array(). See ?extract_array in the S4Arrays package for more information about the seed contract. This makes them de facto array-like objects. However, end users will never interact with them directly, except for the root of the tree which is the DelayedArray object itself and the only node in the tree that they are able to see and touch.

is_noop() can only be called on a DelayedSubset, DelayedAperm, or DelayedSetDimnames object at the moment, and will return TRUE if the object represents a no-op.

Note

The DelayedOp virtual class and its 8 concrete subclasses are used inside a DelayedArray object to represent delayed operations carried by the object. They're never exposed to the end user and are not intended to be manipulated directly.

See also