function template

std::atan

<valarray>
template<class T> valarray<T> atan (const valarray<T>& x);
Compute arc tangent of valarray elements
Returns a valarray object containing the principal value of the arc tangent of all the elements of x, expressed in radians.

This function overloads cmath's atan function.

Parameters

x
valarray containing elements of a type for which the unary function atan is defined.

Return value

A valarray object with the arc tangent values of the elements of x.

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
// atan valarray example
#include <iostream>
#include <cmath>
#include <valarray>
using namespace std;

int main ()
{
  double val[] = {0.0, 0.25, 0.5, 0.75, 1.0};
  valarray<double> foo (val,5);

  valarray<double> bar = atan (foo);

  cout << "foo: ";
  for (size_t i=0; i<foo.size(); ++i)
	  cout << foo[i] << ' ';
  cout << endl;

  cout << "bar: ";
  for (size_t i=0; i<bar.size(); ++i)
	  cout << bar[i] << ' ';
  cout << endl;

  return 0;
}


Output:

foo: 0 0.25 0.5 0.75 1
bar: 0 0.244979 0.463648 0.643501 0.785398

See also