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"PackedArray" (Compiled Type)

"PackedArray"::[type,rank]

represents a packed array composite type with elements of specified type and rank.

Details

  • "PackedArray" can be used in Typed and related constructs to specify a type.
  • "PackedArray" objects are automatically memory managed.
  • Only elements that have a type of "MachineInteger", "Real64" or "ComplexReal64" can be stored in a "PackedArray".

Constructors

  • Packed arrays can be created with List in compiled code. »
  • CreateTypeInstance["PackedArray"::[type,rank],array] constructs a copy of array.
  • CreateTypeInstance["PackedArray"::[type,1],carr,len] constructs a packed array from a "CArray" carr with length len. carr can optionally be wrapped in "Managed".

Properties

  • Information[array,"ElementType"] for array of type "PackedArray"::[type,rank] gives type .

Conversions

    Expressions

  • "PackedArray" objects can be converted to and from List objects of the appropriate form. For a List object to be converted to an object of type "PackedArray"::[type,rank], it must represent a rectangular array with the specified rank and element type.

    • "ListVector"

  • "PackedArray" objects can be converted to and from "ListVector" objects.

Runtime Errors

    ArrayPartError

  • Elements with types constructed from "PackedArray" can give a runtime error if used in an operation that extracts or sets parts.

Examples

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Basic Examples  (2)Summary of the most common use cases

"PackedArray" can be used as an input and output from a CompiledCodeFunction:

In[1]:=1
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-ck3oom
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-fgxe20
Out[2]=2

Create a packed array in compiled code:

In[1]:=1
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-pebb7s
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-77c40z
Out[2]=2

Scope  (1)Survey of the scope of standard use cases

"MachineInteger" is useful for working with "PackedArray", since this takes integers of the native size for the architecture:

In[1]:=1
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-89z3hp
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-pldos5
Out[2]=2

Possible Issues  (1)Common pitfalls and unexpected behavior

Part access can cause an error while running the function. The computation is terminated, a message is issued and the Wolfram Engine is used to compute the result:

In[1]:=1
✖
https://wolfram.com/xid/0e0r940ly8v3wzewmk2gpsrlzu-q0ndn0
Out[1]=1