Stan Math Library  2.11.0
reverse mode automatic differentiation
lb_constrain.hpp
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1 #ifndef STAN_MATH_PRIM_SCAL_FUN_LB_CONSTRAIN_HPP
2 #define STAN_MATH_PRIM_SCAL_FUN_LB_CONSTRAIN_HPP
3 
4 #include <boost/math/tools/promotion.hpp>
6 #include <cmath>
7 #include <limits>
8 
9 namespace stan {
10 
11  namespace math {
12  // LOWER BOUND
13 
33  template <typename T, typename TL>
34  inline
35  T lb_constrain(const T x, const TL lb) {
36  using std::exp;
37  if (lb == -std::numeric_limits<double>::infinity())
38  return identity_constrain(x);
39  return exp(x) + lb;
40  }
41 
58  template <typename T, typename TL>
59  inline
60  typename boost::math::tools::promote_args<T, TL>::type
61  lb_constrain(const T x, const TL lb, T& lp) {
62  using std::exp;
63  if (lb == -std::numeric_limits<double>::infinity())
64  return identity_constrain(x, lp);
65  lp += x;
66  return exp(x) + lb;
67  }
68 
69 
70  }
71 
72 }
73 
74 #endif
T lb_constrain(const T x, const TL lb)
Return the lower-bounded value for the specified unconstrained input and specified lower bound...
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:10
T identity_constrain(T x)
Returns the result of applying the identity constraint transform to the input.

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