std::cos(std::valarray)
From cppreference.com
Defined in header <valarray> | ||
template<class T > valarray<T> cos(const valarray<T>& va ); | ||
For each element in va computes cosine of the value of the element.
Contents |
[edit]Parameters
va | - | value array to apply the operation to |
[edit]Return value
Value array containing cosines of the values in va.
[edit]Notes
Unqualified function (cos) is used to perform the computation. If such function is not available, std::cos 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 conststd::valarray<T>&except begin() and end()(since C++11), identical functions taking the replacement types shall be added;
- For every function taking two conststd::valarray<T>& arguments, identical functions taking every combination of conststd::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.
[edit]Possible implementation
template<class T> valarray<T> cos(const valarray<T>& va){ valarray<T> other = va;for(T& i : other) i = cos(i); return other;// proxy object may be returned} |
[edit]Example
Run this code
#include <cmath>#include <iomanip>#include <iostream>#include <valarray> void show(constchar* title, conststd::valarray<float>& data){constint w{9};std::cout<<std::setw(w)<< title <<" | ";for(float x : data)std::cout<<std::setw(w)<< x <<" | ";std::cout<<'\n';} int main(){conststd::valarray<float> x{.1, .2, .3, .4};constauto sin =std::sin(x);constauto cos =std::cos(x);constauto z =(sin * sin)+(cos * cos); show("x", x); show("sin(x)", sin); show("cos(x)", cos); show("z", z);}
Output:
x | 0.1 | 0.2 | 0.3 | 0.4 | sin(x) | 0.0998334 | 0.198669 | 0.29552 | 0.389418 | cos(x) | 0.995004 | 0.980067 | 0.955337 | 0.921061 | z | 1 | 1 | 1 | 1 |
[edit]See also
applies the function std::sin to each element of valarray (function template) | |
applies the function std::tan to each element of valarray (function template) | |
applies the function std::acos to each element of valarray (function template) | |
(C++11)(C++11) | computes cosine (cos(x)) (function) |
computes cosine of a complex number (cos(z)) (function template) |