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 // atan(const valarray<T>& x);
17
18 #include <valarray>
19 #include <cassert>
20 #include <sstream>
21 #include <cstddef>
22
is_about(double x,double y,int p)23 bool 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
main()35 int main()
36 {
37 {
38 typedef double T;
39 T a1[] = {-.9, -.5, 0., .5, .75};
40 T a3[] = {-7.3281510178650666e-01,
41 -4.6364760900080615e-01,
42 0.0000000000000000e+00,
43 4.6364760900080615e-01,
44 6.4350110879328437e-01};
45 const unsigned N = sizeof(a1)/sizeof(a1[0]);
46 std::valarray<T> v1(a1, N);
47 std::valarray<T> v3 = atan(v1);
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