CDPL.Math.Slice Class Reference

Index slice ( \( start, stride, size \)) used for strided slicing of vector and matrix expressions. More...

Inheritance diagram for CDPL.Math.Slice:

Public Member Functions
None	__init__ ()
	Constructs an empty slice ( \( 0, 0, 0 \)).
None	__init__ (Slice s)
	Initializes a copy of the Slice instance s. More...
None	__init__ (int start, int stride, int size)
	Constructs the slice (start, stride, size). More...
int	getStart ()
	Returns the starting global index. More...
int	getStride ()
	Returns the signed step size between consecutive entries. More...
int	getSize ()
	Returns the number of entries in the slice. More...
bool	isEmpty ()
	Tells whether the slice is empty. More...
int	getIndex (int i)
Slice	assign (Slice s)
	Replaces the current state of self with a copy of the state of the Slice instance s. More...
None	swap (Slice s)
	Swaps the contents of self and s. More...
int	getObjectID ()
	Returns the numeric identifier (ID) of the wrapped C++ class instance. More...
bool	__eq__ (Slice s)
	Equality comparison. More...
bool	__ne__ (Slice s)
	Inequality comparison. More...
int	__call__ (int i)
	Maps the local position i to the global index \( start + i \cdot stride \). More...
int	__getitem__ (int i)

Properties
	objectID = property(getObjectID)
	start = property(getStart)
	stride = property(getStride)
	size = property(getSize)

Detailed Description

Index slice ( \( start, stride, size \)) used for strided slicing of vector and matrix expressions.

Local position i is mapped to the global index \( start + i \cdot stride \). Negative strides (reverse iteration) are supported as long as the resulting indices stay non-negative.

Constructor & Destructor Documentation

__init__() [1/2]

None CDPL.Math.Slice.__init__

(

Slice

s

)

Initializes a copy of the Slice instance s.

Parameters

s	The Slice instance to copy.

__init__() [2/2]

None CDPL.Math.Slice.__init__	(	int	start,
		int	stride,
		int	size
	)

Constructs the slice (start, stride, size).

Parameters

start	The starting global index.
stride	The signed step size between consecutive entries.
size	The number of entries.

Exceptions

Base.RangeError

if the slice would produce a negative global index.

Member Function Documentation

getStart()

int CDPL.Math.Slice.getStart

(

)

Returns the starting global index.

Returns

The starting index.

getStride()

int CDPL.Math.Slice.getStride

(

)

Returns the signed step size between consecutive entries.

Returns

The stride.

getSize()

int CDPL.Math.Slice.getSize

(

)

Returns the number of entries in the slice.

Returns

The slice size.

isEmpty()

bool CDPL.Math.Slice.isEmpty

(

)

Tells whether the slice is empty.

Returns

True if the slice contains no entries, and False otherwise.

getIndex()

int CDPL.Math.Slice.getIndex

(

int

i

)

Parameters

i

Returns

assign()

Slice CDPL.Math.Slice.assign

(

Slice

s

)

Replaces the current state of self with a copy of the state of the Slice instance s.

Parameters

s	The Slice instance to copy.

Returns

self

swap()

None CDPL.Math.Slice.swap

(

Slice

s

)

Swaps the contents of self and s.

Parameters

s	The other slice.

getObjectID()

int CDPL.Math.Slice.getObjectID

(

)

Returns the numeric identifier (ID) of the wrapped C++ class instance.

Different Python Slice instances may reference the same underlying C++ class instance. The commonly used Python expression a is not b thus cannot tell reliably whether the two Slice instances a and b reference different C++ objects. The numeric identifier returned by this method allows to correctly implement such an identity test via the simple expression a.getObjectID() != b.getObjectID().

Returns

The numeric ID of the internally referenced C++ class instance.

__eq__()

bool CDPL.Math.Slice.__eq__

(

Slice

s

)

Equality comparison.

Parameters

s	The other slice.

Returns

True if both slices have the same start, stride and size, and False otherwise.

__ne__()

bool CDPL.Math.Slice.__ne__

(

Slice

s

)

Inequality comparison.

Parameters

s	The other slice.

Returns

True if the slices differ in start, stride or size, and False otherwise.

__call__()

int CDPL.Math.Slice.__call__

(

int

i

)

Maps the local position i to the global index \( start + i \cdot stride \).

Parameters

i	The zero-based local position.

Returns

The global index.

Exceptions

Base.IndexError

if i is not in the range \( [0, size) \).

__getitem__()

int CDPL.Math.Slice.__getitem__

(

int

i

)

Parameters

i

Returns