1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// <valarray>
11
12// template<class T> class valarray;
13
14// template<class T>
15//   valarray<T>
16//   atan2(const valarray<T>& x, const T& y);
17
18#include <valarray>
19#include <cassert>
20#include <sstream>
21#include <cstddef>
22
23bool is_about(double x, double y, int p)
24{
25    std::ostringstream o;
26    o.precision(p);
27    scientific(o);
28    o << x;
29    std::string a = o.str();
30    o.str("");
31    o << y;
32    return a == o.str();
33}
34
35int main()
36{
37    {
38        typedef double T;
39        T a1[] = {-.9, -.5, 0., .5, .75};
40        T a3[] = {-8.7605805059819342e-01,
41                  -5.8800260354756750e-01,
42                   0.0000000000000000e+00,
43                   5.8800260354756750e-01,
44                   7.8539816339744828e-01};
45        const unsigned N = sizeof(a1)/sizeof(a1[0]);
46        std::valarray<T> v1(a1, N);
47        std::valarray<T> v3 = atan2(v1, .75);
48        assert(v3.size() == v1.size());
49        for (std::size_t i = 0; i < v3.size(); ++i)
50            assert(is_about(v3[i], a3[i], 10));
51    }
52}
53