std:: cosh (std::valarray)

For each element in va computes hyperbolic cosine of the value of the element.

Parameters

Return value

Value array containing hyperbolic cosine of the values in va .

Notes

Unqualified function ( cosh ) is used to perform the computation. If such function is not available, std:: cosh 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.
• For every function taking a const std:: valarray < T > & except begin() and end() (since C++11) , identical functions taking the replacement types shall be added;
• For every function taking two const std:: valarray < T > & arguments, identical functions taking every combination of const std:: valarray < T > & and replacement types shall be added.
• 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> cosh(const valarray<T>& va)
{
    valarray<T> other = va;
    for (T& i : other)
        i = cosh(i);
 
    return other; // proxy object may be returned
}

Example

#include <cmath>
#include <iomanip>
#include <iostream>
#include <valarray>
 
void show(const char* title, const std::valarray<float>& data)
{
    const int w{9};
    std::cout << std::setw(w) << title << " | ";
    for (float x : data)
        std::cout << std::setw(w) << x << " | ";
    std::cout << '\n';
}
 
int main()
{
    const std::valarray<float> x{.1, .2, .3, .4};
    const auto sinh = std::sinh(x);
    const auto cosh = std::cosh(x);
    const auto z = (cosh * cosh) - (sinh * sinh);
 
    show("x", x);
    show("sinh(x)", sinh);
    show("cosh(x)", cosh);
    show("z", z);
}

        x |       0.1 |       0.2 |       0.3 |       0.4 | 
  sinh(x) |  0.100167 |  0.201336 |   0.30452 |  0.410752 | 
  cosh(x) |     1.005 |   1.02007 |   1.04534 |   1.08107 | 
        z |         1 |         1 |         1 |         1 |

See also