Class CursorArray<CursorType>

A multidimensional array of objects which share a single storage block.

Inheritance
Object
CursorArray<CursorType>
Implements
ICursorArray<CursorType>
IEnumerable<CursorType>
Inherited Members
Namespace: Microsoft.ML.Probabilistic.Collections
Assembly: Microsoft.ML.Probabilistic.dll
Syntax
public class CursorArray<CursorType> : ICursor, ICloneable, ICursorArray<CursorType>, IEnumerable<CursorType>, ICursorArray, IEnumerable where CursorType : ICursor
Type Parameters
Name Description
CursorType
Remarks

A CursorArray is meant to behave like an ordinary Array, while being more memory-efficient. Instead of storing multiple instances of the same object type, it uses a single instance as a cursor over a block of data. The cursor acts like a pointer which is targeted at the desired part of the array (via its Start property).

The CursorArray object does not hold a pointer to the actual source data. It is agnostic about the actual type and layout of the data that the cursor is walking over, providing a large degree of flexibility in the implementation of the cursor.

Constructors

CursorArray(CursorType)

Declaration
public CursorArray(CursorType cursor)
Parameters
Type Name Description
CursorType cursor

CursorArray(CursorType, IList<Int32>, IList<Int32>)

Declaration
public CursorArray(CursorType cursor, IList<int> lengths, IList<int> stride)
Parameters
Type Name Description
CursorType cursor
IList<Int32> lengths
IList<Int32> stride

CursorArray(CursorType, Int32[])

Declaration
public CursorArray(CursorType cursor, params int[] lengths)
Parameters
Type Name Description
CursorType cursor
Int32[] lengths

Fields

count

Declaration
protected int[] count
Field Value
Type Description
Int32[]

cursor

Declaration
protected CursorType cursor
Field Value
Type Description
CursorType

dim

Declaration
protected int[] dim
Field Value
Type Description
Int32[]

start

Declaration
protected int start
Field Value
Type Description
Int32

stride

Declaration
protected int[] stride
Field Value
Type Description
Int32[]

Properties

Count

The total number of structures across all dimensions

Declaration
public int Count { get; }
Property Value
Type Description
Int32

Item[Int32]

Retrieve an object by linear index.

Declaration
public CursorType this[int index] { get; }
Parameters
Type Name Description
Int32 index
Property Value
Type Description
CursorType
Remarks

If the array is multidimensional, this will index the elements sequentially in row-major order, i.e. the rightmost dimension varies fastest.

The result is a volatile cursor object, which becomes invalid on the next indexer call. This can be a source of bugs, e.g. f(a[i],a[j]) will not work. If you want to save a result across calls, you must make a ReferenceClone, as in: f(a[i].ReferenceClone(), a[j]).

Item[Int32[]]

Retrieve an object by multidimensional index.

Declaration
public CursorType this[params int[] index] { get; }
Parameters
Type Name Description
Int32[] index
Property Value
Type Description
CursorType
Remarks

The result is a volatile cursor object, which becomes invalid on the next indexer call. This can be a source of bugs, e.g. f(a[i],a[j]) will not work. If you want to save a result across calls, you must make a ReferenceClone, as in: f(a[i].ReferenceClone(), a[j]).

Lengths

The size of each dimension of the array.

Declaration
public IList<int> Lengths { get; protected set; }
Property Value
Type Description
IList<Int32>

Rank

The number of dimensions of the array.

Declaration
public int Rank { get; }
Property Value
Type Description
Int32

Start

Declaration
public int Start { get; set; }
Property Value
Type Description
Int32

Stride

Declaration
public int[] Stride { get; }
Property Value
Type Description
Int32[]

Methods

CheckCompatible(ICursorArray)

Declaration
public void CheckCompatible(ICursorArray that)
Parameters
Type Name Description
ICursorArray that

Clone()

Declaration
public virtual object Clone()
Returns
Type Description
Object

CreateSourceArray(Int32)

Declaration
public void CreateSourceArray(int nRecords)
Parameters
Type Name Description
Int32 nRecords

ForEach(ICursorArray, ICursorArray, Action)

Invoke an element-wise action across three arrays.

Declaration
public void ForEach(ICursorArray a, ICursorArray b, Action action)
Parameters
Type Name Description
ICursorArray a

An array of the same size as this. Can be the same object as this.
ICursorArray b

An array of the same size as this. Can be the same object as this.
Action action

A delegate which accesses the array cursors.

ForEach(ICursorArray, Action)

Invoke an element-wise action across two arrays.

Declaration
public void ForEach(ICursorArray that, Action action)
Parameters
Type Name Description
ICursorArray that

An array of the same size as this. Can be the same object as this.
Action action

A delegate which accesses the array cursors.

ForEach(Action)

Invoke an action for each element of an array.

Declaration
public void ForEach(Action action)
Parameters
Type Name Description
Action action

A delegate which accesses the array cursor.

GetEnumerator()

Declaration
public IEnumerator<CursorType> GetEnumerator()
Returns
Type Description
IEnumerator<CursorType>

GetLength(Int32)

Declaration
public int GetLength(int dimension)
Parameters
Type Name Description
Int32 dimension
Returns
Type Description
Int32

IsCompatibleWith(ICursorArray)

Declaration
public bool IsCompatibleWith(ICursorArray that)
Parameters
Type Name Description
ICursorArray that
Returns
Type Description
Boolean

IsCompatibleWith(Array)

Declaration
public bool IsCompatibleWith(Array that)
Parameters
Type Name Description
Array that
Returns
Type Description
Boolean

LinearIndexToMultidimensionalIndex(Int32, IList<Int32>)

Declaration
public void LinearIndexToMultidimensionalIndex(int index, IList<int> indexList)
Parameters
Type Name Description
Int32 index
IList<Int32> indexList

MoveTo(Int32)

Position the cursor at a linear index.

Declaration
public void MoveTo(int index)
Parameters
Type Name Description
Int32 index

MoveTo(Int32[])

Position the cursor at a multidimensional index.

Declaration
public void MoveTo(params int[] index)
Parameters
Type Name Description
Int32[] index

ReferenceClone()

Declaration
public virtual ICursor ReferenceClone()
Returns
Type Description
ICursor

UpdateCounts()

Declaration
protected void UpdateCounts()

Explicit Interface Implementations

ICursor.Count

Declaration
int ICursor.Count { get; }
Returns
Type Description
Int32

ICursorArray.Item[Int32]

Declaration
object ICursorArray.this[int index] { get; }
Parameters
Type Name Description
Int32 index
Returns
Type Description
Object

ICursorArray.Item[Int32[]]

Declaration
object ICursorArray.this[params int[] index] { get; }
Parameters
Type Name Description
Int32[] index
Returns
Type Description
Object

IEnumerable.GetEnumerator()

Declaration
IEnumerator IEnumerable.GetEnumerator()
Returns
Type Description
IEnumerator

Implements

Extension Methods