check_simplex.hpp
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1 #ifndef STAN_MATH_PRIM_MAT_ERR_CHECK_SIMPLEX_HPP
2 #define STAN_MATH_PRIM_MAT_ERR_CHECK_SIMPLEX_HPP
3 
10 #include <sstream>
11 #include <string>
12 
13 namespace stan {
14 namespace math {
15 
16 /**
17  * Check if the specified vector is simplex.
18  * To be a simplex, all values must be greater than or equal to 0
19  * and the values must sum to 1.
20  *
21  * A valid simplex is one where the sum of hte elements is equal
22  * to 1. This function tests that the sum is within the tolerance
23  * specified by <code>CONSTRAINT_TOLERANCE</code>. This function
24  * only accepts Eigen vectors, statically typed vectors, not
25  * general matrices with 1 column.
26  *
27  * @tparam T_prob Scalar type of the vector
28  *
29  * @param function Function name (for error messages)
30  * @param name Variable name (for error messages)
31  * @param theta Vector to test.
32  *
33  * @throw <code>std::invalid_argument</code> if <code>theta</code>
34  * is a 0-vector.
35  * @throw <code>std::domain_error</code> if the vector is not a
36  * simplex or if any element is <code>NaN</code>.
37  */
38 template <typename T_prob>
39 void check_simplex(const char* function, const char* name,
40  const Eigen::Matrix<T_prob, Eigen::Dynamic, 1>& theta) {
41  using Eigen::Dynamic;
42  using Eigen::Matrix;
43 
44  typedef typename index_type<Matrix<T_prob, Dynamic, 1> >::type size_t;
45 
46  check_nonzero_size(function, name, theta);
47  if (!(fabs(1.0 - theta.sum()) <= CONSTRAINT_TOLERANCE)) {
48  std::stringstream msg;
49  T_prob sum = theta.sum();
50  msg << "is not a valid simplex.";
51  msg.precision(10);
52  msg << " sum(" << name << ") = " << sum << ", but should be ";
53  std::string msg_str(msg.str());
54  domain_error(function, name, 1.0, msg_str.c_str());
55  }
56  for (size_t n = 0; n < theta.size(); n++) {
57  if (!(theta[n] >= 0)) {
58  std::ostringstream msg;
59  msg << "is not a valid simplex. " << name << "["
60  << n + stan::error_index::value << "]"
61  << " = ";
62  std::string msg_str(msg.str());
63  domain_error(function, name, theta[n], msg_str.c_str(),
64  ", but should be greater than or equal to 0");
65  }
66  }
67 }
68 } // namespace math
69 } // namespace stan
70 #endif
fvar< T > sum(const std::vector< fvar< T > > &m)
Definition: sum.hpp:20
const XML_Char * name
Definition: expat.h:151
void check_simplex(const char *function, const char *name, const Eigen::Matrix< T_prob, Eigen::Dynamic, 1 > &theta)
void check_nonzero_size(const char *function, const char *name, const T_y &y)
fvar< T > fabs(const fvar< T > &x)
Definition: fabs.hpp:15
const double CONSTRAINT_TOLERANCE
void domain_error(const char *function, const char *name, const T &y, const char *msg1, const char *msg2)
enum BeamMode string