3.4 KiB
[class.slice]
29 Numerics library [numerics]
29.6 Numeric arrays [numarray]
29.6.4 Class slice [class.slice]
29.6.4.1 Overview [class.slice.overview]
namespace std {class slice {public: slice(); slice(size_t, size_t, size_t); slice(const slice&);
size_t start() const; size_t size() const; size_t stride() const; friend bool operator==(const slice& x, const slice& y); };}
The slice class represents a BLAS-like slice from an array.
Such a slice is specified by a starting index, a length, and a stride.252
BLAS stands forBasic Linear Algebra Subprograms.
C++ programs can instantiate this class.
See, for example, Dongarra, Du Croz, Duff, and Hammerling:A set of Level 3 Basic Linear Algebra Subprograms; Technical Report MCS-P1-0888, Argonne National Laboratory (USA), Mathematics and Computer Science Division, August, 1988.
29.6.4.2 Constructors [cons.slice]
slice(); slice(size_t start, size_t length, size_t stride);
The default constructor is equivalent to slice(0, 0, 0).
A default constructor is provided only to permit the declaration of arrays of slices.
The constructor with arguments for a slice takes a start, length, and stride parameter.
[Example 1:
slice(3, 8, 2) constructs a slice which selects elements 3,5,7,â¦,17 from an array.
â end example]
29.6.4.3 Access functions [slice.access]
size_t start() const; size_t size() const; size_t stride() const;
Returns: The start, length, or stride specified by a slice object.
Complexity: Constant time.
29.6.4.4 Operators [slice.ops]
friend bool operator==(const slice& x, const slice& y);
Effects: Equivalent to:return x.start() == y.start() && x.size() == y.size() && x.stride() == y.stride();