< cpp‎ | numeric‎ | valarray
Defined in header <valarray>
template< class T >
valarray<T> atan( const valarray<T>& va );

For each element in va computes arc tangent of the value of the element.


va - value array to apply the operation to

Return value

Value array containing arc tangents of the values in va.


Unqualified function (atan) is used to perform the computation. If such function is not available, std::atan is used due to argument dependent lookup.

The function can be implemented with the return type different from std::valarray. In this case, the replacement type has the following properties:

Possible implementation

template<class T>
valarray<T> atan(const valarray<T>& va)
    valarray<T> other = va;
    for (T &i : other) {
        i = atan(i);
    return other;


See also

applies the function std::asin to each element of valarray
(function template)
applies the function std::acos to each element of valarray
(function template)
applies the function std::atan2 to a valarray and a value
(function template)
applies the function std::tan to each element of valarray
(function template)
computes arc tangent (arctan(x))
computes arc tangent of a complex number (arctan(z))
(function template)