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fmin.hpp
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1 #ifndef STAN__AGRAD__FWD__FUNCTIONS__FMIN_HPP
2 #define STAN__AGRAD__FWD__FUNCTIONS__FMIN_HPP
3 
4 #include <stan/agrad/fwd/fvar.hpp>
5 #include <stan/meta/traits.hpp>
6 #include <stan/math/constants.hpp>
7 #include <math.h>
8 #include <stan/meta/likely.hpp>
9 
10 namespace stan {
11 
12  namespace agrad {
13 
14  template <typename T>
15  inline
16  fvar<T>
17  fmin(const fvar<T>& x1, const fvar<T>& x2) {
18  using ::fmin;
19  using stan::math::NOT_A_NUMBER;
20  if (unlikely(boost::math::isnan(x1.val_))) {
21  if (boost::math::isnan(x2.val_))
22  return fvar<T>(fmin(x1.val_,x2.val_),NOT_A_NUMBER);
23  else
24  return fvar<T>(x2.val_, x2.d_);
25  } else if (unlikely(boost::math::isnan(x2.val_)))
26  return fvar<T>(x1.val_,x1.d_);
27  else if(x1.val_ < x2.val_)
28  return fvar<T>(x1.val_, x1.d_);
29  else if(x1.val_ == x2.val_)
30  return fvar<T>(x1.val_, NOT_A_NUMBER);
31  else
32  return fvar<T>(x2.val_, x2.d_);
33  }
34 
35  template <typename T>
36  inline
37  fvar<T>
38  fmin(const double x1, const fvar<T>& x2) {
39  using ::fmin;
40  using stan::math::NOT_A_NUMBER;
41  if (unlikely(boost::math::isnan(x1))) {
42  if (boost::math::isnan(x2.val_))
43  return fvar<T>(fmin(x1,x2.val_),NOT_A_NUMBER);
44  else
45  return fvar<T>(x2.val_, x2.d_);
46  } else if (unlikely(boost::math::isnan(x2.val_)))
47  return fvar<T>(x1,0.0);
48  else if(x1 < x2.val_)
49  return fvar<T>(x1, 0.0);
50  else if(x1 == x2.val_)
51  return fvar<T>(x2.val_, NOT_A_NUMBER);
52  else
53  return fvar<T>(x2.val_, x2.d_);
54  }
55 
56  template <typename T>
57  inline
58  fvar<T>
59  fmin(const fvar<T>& x1, const double x2) {
60  using ::fmin;
61  using stan::math::NOT_A_NUMBER;
62  if (unlikely(boost::math::isnan(x1.val_))) {
63  if (boost::math::isnan(x2))
64  return fvar<T>(fmin(x1.val_,x2),NOT_A_NUMBER);
65  else
66  return fvar<T>(x2, 0.0);
67  } else if (unlikely(boost::math::isnan(x2)))
68  return fvar<T>(x1.val_,x1.d_);
69  else if(x1.val_ < x2)
70  return fvar<T>(x1.val_, x1.d_);
71  else if(x1.val_ == x2)
72  return fvar<T>(x1.val_, NOT_A_NUMBER);
73  else
74  return fvar<T>(x2, 0.0);
75  }
76  }
77 }
78 #endif
boost::math::isnan
bool isnan(const stan::agrad::var &v)
Checks if the given number is NaN.
Definition: boost_fpclassify.hpp:69
stan::agrad::fmin
var fmin(const double &a, const stan::agrad::var &b)
Returns the minimum of a scalar and variable, promoting the scalar to a variable if it is larger (C99...
Definition: fmin.hpp:126
stan::math::NOT_A_NUMBER
const double NOT_A_NUMBER
(Quiet) not-a-number value.
Definition: constants.hpp:53
unlikely
#define unlikely(x)
Definition: likely.hpp:9
stan::agrad::fmin
fvar< T > fmin(const fvar< T > &x1, const fvar< T > &x2)
Definition: fmin.hpp:17
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