[valarray.members]

# 29 Numerics library [[numerics]](./#numerics)

## 29.6 Numeric arrays [[numarray]](numarray#valarray.members)

### 29.6.2 Class template valarray [[template.valarray]](template.valarray#valarray.members)

#### 29.6.2.8 Member functions [valarray.members]

[🔗](#lib:swap,valarray)

`void swap(valarray& v) noexcept;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7933)

*Effects*: *this obtains the value ofv[.](#1.sentence-1)

v obtains the value of *this[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7938)

*Complexity*: Constant[.](#2.sentence-1)

[🔗](#lib:size,valarray)

`size_t size() const;
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7949)

*Returns*: The number of elements in the array[.](#3.sentence-1)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7953)

*Complexity*: Constant time[.](#4.sentence-1)

[🔗](#lib:sum,valarray)

`T sum() const;
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7964)

*Mandates*: operator+= can be applied to operands of type T[.](#5.sentence-1)

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7968)

*Preconditions*: size() > 0 is true[.](#6.sentence-1)

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7972)

*Returns*: The sum of all the elements of the array[.](#7.sentence-1)

If the array has length 1, returns the value of element 0[.](#7.sentence-2)

Otherwise, the returned value is calculated by applyingoperator+= to a copy of an element of the array and
all other elements of the array in an unspecified order[.](#7.sentence-3)

[🔗](#lib:min,valarray)

`T min() const;
`

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7988)

*Preconditions*: size() > 0 is true[.](#8.sentence-1)

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L7992)

*Returns*: The minimum value contained in *this[.](#9.sentence-1)

For an array of length 1, the value of element 0 is returned[.](#9.sentence-2)

For all other array
lengths, the determination is made usingoperator<[.](#9.sentence-3)

[🔗](#lib:max,valarray)

`T max() const;
`

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8007)

*Preconditions*: size() > 0 is true[.](#10.sentence-1)

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8011)

*Returns*: The maximum value contained in *this[.](#11.sentence-1)

For an array of length 1, the value of element 0 is returned[.](#11.sentence-2)

For all other array
lengths, the determination is made usingoperator<[.](#11.sentence-3)

[🔗](#lib:shift,valarray)

`valarray shift(int n) const;
`

[12](#12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8026)

*Returns*: A valarray of length size(), each of whose elements*I* is(*this)[*I* + n] if *I* + n is non-negative and less thansize(), otherwise T()[.](#12.sentence-1)

[*Note [1](#note-1)*:

If element zero is taken as the leftmost element,
a positive value of n shifts the elements left n places, with zero fill[.](#12.sentence-2)

— *end note*]

[13](#13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8040)

[*Example [1](#example-1)*:

If the argument has the value −2,
the first two elements of the result will be [value-initialized](dcl.init#def:value-initialization "9.5 Initializers [dcl.init]"); the third element of the result will be assigned the value
of the first element of *this; etc[.](#13.sentence-1)

— *end example*]

[🔗](#lib:cshift,valarray)

`valarray cshift(int n) const;
`

[14](#14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8054)

*Returns*: A valarray of length size() that is a circular shift of *this[.](#14.sentence-1)

If element zero is taken as
the leftmost element, a non-negative value of n shifts
the elements circularly left n places and a negative
value of n shifts the elements circularly right −n places[.](#14.sentence-2)

[🔗](#lib:apply,valarray)

`valarray apply(T func(T)) const;
valarray apply(T func(const T&)) const;
`

[15](#15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8070)

*Returns*: A valarray whose length is size()[.](#15.sentence-1)

Each element of the returned array is assigned
the value returned by applying the argument function to the
corresponding element of *this[.](#15.sentence-2)

[🔗](#lib:resize,valarray)

`void resize(size_t sz, T c = T());
`

[16](#16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8084)

*Effects*: Changes the length of the *this array to sz and then assigns to each element the value of the second argument[.](#16.sentence-1)

Resizing invalidates all pointers and references to elements in the array[.](#16.sentence-2)