R: DelayedOp objects

DelayedOp-class {DelayedArray}

R Documentation

DelayedOp objects

Description

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 the nodes are array-like objects that must comply with the seed contract i.e. they must support dim(), dimnames(), and extract_array(). See ?extract_array for more information about the seed contract.

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