std::exp(std::valarray)

 

C++

Language

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Utilities library

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Numerics library

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std::valarray

Member functions
valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+ valarray::operator- valarray::operator~ valarray::operator! valarray::operator+= valarray::operator-= valarray::operator*= valarray::operator/= valarray::operator%= valarray::operator&= valarray::operator|= valarray::operator^= valarray::operator<<= valarray::operator>>=
Non-member functions
swap (C++11) begin (C++11) end (C++11) abs exp log log10 pow sqrt sin cos tan asin acos atan atan2 sinh cosh tanh	operator* operator/ operator% operator+ operator- operator^ operator& operator| operator<< operator>> operator&& operator|| operator== operator!= operator< operator> operator<= operator>=
Helper classes
slice_array gslice_array indirect_array	slice gslice mask_array

 

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.

Parameters

va

-

value array to apply the operation to

Return value

Value array containing e raised by the values in va.

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:

• All const member functions of std::valarray are provided.
• std::valarray, std::slice_array, std::gslice_array, std::mask_array and std::indirect_array can be constructed from the replacement type.
• All functions accepting a arguments of type const std::valarray& should also accept the replacement type.
• All functions accepting two arguments of type const std::valarray& should accept every combination of const std::valarray& and the replacement type.
• The return type does not add more than two levels of template nesting over the most deeply-nested argument type.

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 }

Example

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

run this code

#include <iostream>
#include <complex>
#include <valarray>
 
int main()
{
    const double pi = std::acos(-1);
    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(auto n : v2) {
        std::cout << std::fixed << n << '\n';
    }
}

Output:

(1.000000,0.000000)
(0.000000,1.000000)
(-1.000000,0.000000)
(-0.000000,-1.000000)
(1.000000,-0.000000)

See also

exp	returns e raised to the given power (ex) (function)
exp(std::complex)	complex base e exponential (function template)