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

For each element in va computes e raised to the power equal to the value of the element.


[edit] Parameters

va - value array to apply the operation to

[edit] Return value

Value array containing e raised by the values in va.

[edit] Notes

Unqualified function (exp) is used to perform the computation. If such function is not available, std::exp 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:

[edit] Possible implementation

template<class T>
valarray<T> exp(const valarray<T>& va)
    valarray<T> other = va;
    for (T& i : other)
        i = exp(i);
    return other; // proxy object may be returned

[edit] Example

This example demonstrates the Euler's identity e
= -1
and the related exponents.

#include <complex>
#include <iostream>
#include <numbers>
#include <valarray>
int main()
    const double pi = std::numbers::pi;
    std::valarray<std::complex<double>> v =
        {0, 0}, {0, pi / 2}, {0, pi}, {0, 3 * pi / 2}, {0, 2 * pi}
    std::valarray<std::complex<double>> v2 = std::exp(v);
    for (std::cout << std::showpos << std::fixed; auto n : v2)
        std::cout << n << '\n';



[edit] See also

applies the function std::log to each element of valarray
(function template) [edit]
returns e raised to the given power (ex)
(function) [edit]
complex base e exponential
(function template) [edit]