std::tan(std::valarray)(3)

NAME
std::tan(std::valarray) - std::tan(std::valarray)

Synopsis
   Defined in header <valarray>
   template< class T >
   valarray<T> tan( const valarray<T>& va );
   For each element in va computes tangent of the value of the element.

Parameters
   va - value array to apply the operation to

Return value
   Value array containing tangents of the values in va.

Notes
   Unqualified function (tan) is used to perform the computation. If such function is
   not available, std::tan 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> tan(const valarray<T>& va)
   {
       valarray<T> other = va;
       for (T& i : other)
           i = tan(i);
       return other; // proxy object may be returned
   }

Example
// Run this code
 #include <cmath>
 #include <iostream>
 #include <valarray>
 auto show = [](char const* title, const std::valarray<double>& va)
 {
     std::cout << title << " :";
     for (auto x : va)
         std::cout << " " << std::fixed << x;
     std::cout << '\n';
 };
 int main()
 {
     const std::valarray<double> x = {.0, .1, .2, .3};
     const std::valarray<double> y = std::tan(x);
     const std::valarray<double> z = std::atan(y);
     show("x ", x);
     show("y = tan(x) ", y);
     show("z = atan(y)", z);
 }

Output:
 x : 0.000000 0.100000 0.200000 0.300000
 y = tan(x) : 0.000000 0.100335 0.202710 0.309336
 z = atan(y) : 0.000000 0.100000 0.200000 0.300000

See also
   sin(std::valarray) applies the function std::sin to each element of valarray
                       (function template)
   cos(std::valarray) applies the function std::cos to each element of valarray
                       (function template)
   atan(std::valarray) applies the function std::atan to each element of valarray
                       (function template)
   tan
   tanf computes tangent (\({\small\tan{x}}\)tan(x))
   tanl (function)
   (C++11)
   (C++11)
   tan(std::complex) computes tangent of a complex number (\({\small\tan{z}}\)tan(z))
                       (function template)

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