# Vector

#### Description

The templated class `vector<T, A>` is the base container adaptor for dense vectors. For a n-dimensional vector and 0 <= i < n every element vi is mapped to the i-th element of the container.

#### Example

    #include <boost/numeric/ublas/vector.hpp>

    #include <boost/numeric/ublas/io.hpp>

    int main () {

        using namespace boost::numeric::ublas;

        vector<double> v (3);

        for (unsigned i = 0; i < v.size (); ++ i)

            v (i) = i;

        std::cout << v << std::endl;

    }

#### Definition

Defined in the header vector.hpp.

#### Template parameters

Parameter | Description | Default
--- | --- | ---
`T` | The type of object stored in the vector. |
`A` | The type of the adapted array. [1] | `unbounded_array<T>`

#### Model of

Vector .

#### Type requirements

None, except for those imposed by the requirements of Vector .

#### Public base classes

`vector_expression<vector<T, A> >`

#### Members

Member | Description
--- | ---
`vector ()` | Allocates an uninitialized `vector` that holds zero elements.
`vector (size_type size)` | Allocates an uninitialized `vector` that holds `size` elements.
`vector (const vector &v)` | The copy constructor.
`template<class AE> vector (const vector_expression<AE> &ae)` | The extended copy constructor.
`void resize (size_type size)` | Reallocates a `vector` to hold `size` elements. The content of the `vector` is not preserved.
`size_type size () const` | Returns the size of the `vector`.
`const_reference operator () (size_type i) const` | Returns a `const` reference of the `i` -th element.
`reference operator () (size_type i)` | Returns a reference of the `i`-th element.
`const_reference operator [] (size_type i) const` | Returns a `const` reference of the `i` -th element.
`reference operator [] (size_type i)` | Returns a reference of the `i`-th element.
`vector &operator = (const vector &v)` | The assignment operator.
`vector &assign_temporary (vector &v)` | Assigns a temporary. May change the vector `v`.
`template<class AE> vector &operator = (const vector_expression<AE> &ae)` | The extended assignment operator.
`template<class AE> vector &assign (const vector_expression<AE> &ae)` | Assigns a vector expression to the vector. Left and right hand side of the assignment should be independent.
`template<class AE> vector &operator += (const vector_expression<AE> &ae)` | A computed assignment operator. Adds the vector expression to the vector.
`template<class AE> vector &plus_assign (const vector_expression<AE> &ae)` | Adds a vector expression to the vector. Left and right hand side of the assignment should be independent.
`template<class AE> vector &operator -= (const vector_expression<AE> &ae)` | A computed assignment operator. Subtracts the vector expression from the vector.
`template<class AE> vector &minus_assign (const vector_expression<AE> &ae)` | Subtracts a vector expression from the vector. Left and right hand side of the assignment should be independent.
`template<class AT> vector &operator *= (const AT &at)` | A computed assignment operator. Multiplies the vector with a scalar.
`template<class AT> vector &operator /= (const AT &at)` | A computed assignment operator. Divides the vector through a scalar.
`void swap (vector &v)` | Swaps the contents of the vectors.
`void insert (size_type i, const_reference t)` | Inserts the value `t` at the `i`-th element.
`void erase (size_type i)` | Erases the value at the `i`-th element.
`void clear ()` | Clears the vector.
`const_iterator begin () const` | Returns a `const_iterator` pointing to the beginning of the `vector`.
`const_iterator end () const` | Returns a `const_iterator` pointing to the end of the `vector`.
`iterator begin ()` | Returns a `iterator` pointing to the beginning of the `vector`.
`iterator end ()` | Returns a `iterator` pointing to the end of the `vector`.
`const_reverse_iterator rbegin () const` | Returns a `const_reverse_iterator` pointing to the beginning of the reversed `vector`.
`const_reverse_iterator rend () const` | Returns a `const_reverse_iterator` pointing to the end of the reversed `vector`.
`reverse_iterator rbegin ()` | Returns a `reverse_iterator` pointing to the beginning of the reversed `vector`.
`reverse_iterator rend ()` | Returns a `reverse_iterator` pointing to the end of the reversed `vector`.

#### Notes

[1] Supported parameters for the adapted array are `unbounded_array<T>` , `bounded_array<T>` and `std::vector<T>` .

## Unit Vector

#### Description

The templated class `unit_vector<T>` represents canonical unit vectors. For the k-th n-dimensional canonical unit vector and 0 <= i < n holds uki = 0, if i <> k, and uki = 1.

#### Example

    #include <boost/numeric/ublas/vector.hpp>

    #include <boost/numeric/ublas/io.hpp>

    int main () {

        using namespace boost::numeric::ublas;

        for (int i = 0; i < 3; ++ i) {

            unit_vector<double> v (3, i);

            std::cout << v << std::endl;

        }

    }

#### Definition

Defined in the header vector.hpp.

#### Template parameters

Parameter | Description | Default
--- | --- | ---
`T` | The type of object stored in the vector. |

#### Model of

Vector Expression .

#### Type requirements

None, except for those imposed by the requirements of Vector Expression .

#### Public base classes

`vector_expression<unit_vector<T> >`

#### Members

Member | Description
--- | ---
`unit_vector ()` | Constructs an `unit_vector` that holds zero elements.
`unit_vector (size_type size, size_type index)` | Constructs the `index`-th `unit_vector` that holds `size` elements.
`unit_vector (const unit_vector &v)` | The copy constructor.
`void resize (size_type size)` | Resizes a `unit_vector` to hold `size` elements.
`size_type size () const` | Returns the size of the `unit_vector`.
`size_type index () const` | Returns the index of the `unit_vector`.
`const_reference operator () (size_type i) const` | Returns the value of the `i`-th element.
`const_reference operator [] (size_type i) const` | Returns the value of the `i`-th element.
`unit_vector &operator = (const unit_vector &v)` | The assignment operator.
`unit_vector &assign_temporary (unit_vector &v)` | Assigns a temporary. May change the unit vector `v` .
`void swap (unit_vector &v)` | Swaps the contents of the unit vectors.
`const_iterator begin () const` | Returns a `const_iterator` pointing to the beginning of the `unit_vector`.
`const_iterator end () const` | Returns a `const_iterator` pointing to the end of the `unit_vector`.
`const_reverse_iterator rbegin () const` | Returns a `const_reverse_iterator` pointing to the beginning of the reversed `unit_vector`.
`const_reverse_iterator rend () const` | Returns a `const_reverse_iterator` pointing to the end of the reversed `unit_vector`.

## Zero Vector

#### Description

The templated class `zero_vector<T>` represents zero vectors. For a n-dimensional zero vector and 0 <= i < n holds zi = 0.

#### Example

    #include <boost/numeric/ublas/vector.hpp>

    #include <boost/numeric/ublas/io.hpp>

    int main () {

        using namespace boost::numeric::ublas;

        zero_vector<double> v (3);

        std::cout << v << std::endl;

    }

#### Definition

Defined in the header vector.hpp.

#### Template parameters

Parameter | Description | Default
--- | --- | ---
`T` | The type of object stored in the vector. |

#### Model of

Vector Expression .

#### Type requirements

None, except for those imposed by the requirements of Vector Expression .

#### Public base classes

`vector_expression<zero_vector<T> >`

#### Members

Member | Description
--- | ---
`zero_vector ()` | Constructs a `zero_vector` that holds zero elements.
`zero_vector (size_type size)` | Constructs a `zero_vector` that holds `size` elements.
`zero_vector (const zero_vector &v)` | The copy constructor.
`void resize (size_type size)` | Resizes a `zero_vector` to hold `size` elements.
`size_type size () const` | Returns the size of the `zero_vector`.
`const_reference operator () (size_type i) const` | Returns the value of the `i`-th element.
`const_reference operator [] (size_type i) const` | Returns the value of the `i`-th element.
`zero_vector &operator = (const zero_vector &v)` | The assignment operator.
`zero_vector &assign_temporary (zero_vector &v)` | Assigns a temporary. May change the zero vector `v` .
`void swap (zero_vector &v)` | Swaps the contents of the zero vectors.
`const_iterator begin () const` | Returns a `const_iterator` pointing to the beginning of the `zero_vector`.
`const_iterator end () const` | Returns a `const_iterator` pointing to the end of the `zero_vector`.
`const_reverse_iterator rbegin () const` | Returns a `const_reverse_iterator` pointing to the beginning of the reversed `zero_vector`.
`const_reverse_iterator rend () const` | Returns a `const_reverse_iterator` pointing to the end of the reversed `zero_vector`.

Copyright (©) 2000-2002 Joerg Walter, Mathias Koch
Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided ``as is'' without express or implied warranty, and with no claim as to its suitability for any purpose.

Last revised: 1/15/2003