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      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 //   log(const valarray<T>& x);
     17 
     18 #include <valarray>
     19 #include <cassert>
     20 #include <sstream>
     21 #include <cstddef>
     22 
     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 
     35 int main()
     36 {
     37     {
     38         typedef double T;
     39         T a1[] = {.5, .75, 1, 3, 7};
     40         T a3[] = {-6.9314718055994529e-01,
     41                   -2.8768207245178090e-01,
     42                    0.0000000000000000e+00,
     43                    1.0986122886681098e+00,
     44                    1.9459101490553132e+00};
     45         const unsigned N = sizeof(a1)/sizeof(a1[0]);
     46         std::valarray<T> v1(a1, N);
     47         std::valarray<T> v3 = log(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