From cppreference.com
template<classT>valarray<T>atan(constvalarray<T>&va);For each element in va computes arc tangent of the value of the element.
Parameters
va - value array to apply the operation to Return value
Value array containing arc tangents of the values in va.
Notes
Unqualified function (atan) is used to perform the computation. If such function is not available, std::atan is used due to
.
The function can be implemented with the return type different from
. In this case, the replacement type has the following properties:
All const member functions of
are provided.
,
,
,
and
can be constructed from the replacement type.
For every function taking a conststd::valarray<T>&except
and
(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.
Possible implementation
template<classT>valarray<T>atan(constvalarray<T>&va){valarray<T>other=va;for(T&i:other)i=atan(i);returnother;// proxy object may be returned}Example
Run this code
#include<algorithm>#include<cmath>#include<iostream>#include<valarray>autoshow=[](charconst*title,conststd::valarray<float>&va){std::cout<<title<<" :";std::for_each(std::begin(va),std::end(va),[](constfloatx){std::cout<<" "<<std::fixed<<x;});std::cout<<'\n';};intmain(){conststd::valarray<float>x={.1f,.3f,.6f,.9f};conststd::valarray<float>f=std::atan(x);conststd::valarray<float>g=std::tan(f);show("x ",x);show("f = atan(x)",f);show("g = tan(f) ",g);}Output:
x : 0.100000 0.300000 0.600000 0.900000 f = atan(x) : 0.099669 0.291457 0.540420 0.732815 g = tan(f) : 0.100000 0.300000 0.600000 0.900000 See also
applies the function
to each element of valarray
(function template)
applies the function
to each element of valarray
(function template)
applies the function
to a valarray and a value
(function template)
applies the function
to each element of valarray
(function template)
(C++11)(C++11)
computes arc tangent (arctan(x))
(function)
(C++11)
computes arc tangent of a complex number (arctan(z))
(function template)