add beta_neg_binomial_lccdf test back

Author: lingium

test/prob/beta_neg_binomial/beta_neg_binomial_ccdf_log_test.hpp

@@ -0,0 +1,96 @@
+// Arguments: Ints, Doubles, Doubles, Doubles
+#include <stan/math/prim/prob/beta_neg_binomial_lccdf.hpp>
+#include <stan/math/prim/fun/lbeta.hpp>
+#include <stan/math/prim/fun/lgamma.hpp>
+
+using stan::math::var;
+using std::numeric_limits;
+using std::vector;
+
+class AgradCcdfLogBetaNegBinomial : public AgradCcdfLogTest {
+ public:
+  void valid_values(vector<vector<double>>& parameters,
+                    vector<double>& ccdf_log) {
+    vector<double> param(4);
+
+    param[0] = 0;    // n
+    param[1] = 1.0;  // r
+    param[2] = 5.0;  // alpha
+    param[3] = 1.0;  // beta
+    parameters.push_back(param);
+    ccdf_log.push_back(std::log(1.0 - 0.833333333333333));  // expected ccdf_log
+  }
+
+  void invalid_values(vector<size_t>& index, vector<double>& value) {
+    // n
+
+    // r
+    index.push_back(1U);
+    value.push_back(0.0);
+
+    index.push_back(1U);
+    value.push_back(-1.0);
+
+    index.push_back(1U);
+    value.push_back(std::numeric_limits<double>::infinity());
+
+    // alpha
+    index.push_back(2U);
+    value.push_back(0.0);
+
+    index.push_back(2U);
+    value.push_back(-1.0);
+
+    index.push_back(2U);
+    value.push_back(std::numeric_limits<double>::infinity());
+
+    // beta
+    index.push_back(3U);
+    value.push_back(0.0);
+
+    index.push_back(3U);
+    value.push_back(-1.0);
+
+    index.push_back(3U);
+    value.push_back(std::numeric_limits<double>::infinity());
+  }
+
+  // BOUND INCLUDED IN ORDER FOR TEST TO PASS WITH CURRENT FRAMEWORK
+  bool has_lower_bound() { return false; }
+
+  bool has_upper_bound() { return false; }
+
+  template <typename T_n, typename T_r, typename T_size1, typename T_size2,
+            typename T4, typename T5>
+  stan::return_type_t<T_r, T_size1, T_size2> ccdf_log(const T_n& n,
+                                                      const T_r& r,
+                                                      const T_size1& alpha,
+                                                      const T_size2& beta,
+                                                      const T4&, const T5&) {
+    return stan::math::beta_neg_binomial_lccdf(n, r, alpha, beta);
+  }
+
+  template <typename T_n, typename T_r, typename T_size1, typename T_size2,
+            typename T4, typename T5>
+  stan::return_type_t<T_r, T_size1, T_size2> ccdf_log_function(
+      const T_n& n, const T_r& r, const T_size1& alpha, const T_size2& beta,
+      const T4&, const T5&) {
+    using stan::math::lbeta;
+    using stan::math::lgamma;
+    using stan::math::log1m;
+    using stan::math::log_sum_exp;
+    using std::vector;
+
+    vector<stan::return_type_t<T_r, T_size1, T_size2>> lpmf_values;
+
+    for (int i = 0; i <= n; i++) {
+      auto lpmf = lbeta(i + r, alpha + beta) - lbeta(r, alpha)
+                  + lgamma(i + beta) - lgamma(i + 1) - lgamma(beta);
+      lpmf_values.push_back(lpmf);
+    }
+
+    auto log_cdf = log_sum_exp(lpmf_values);
+
+    return log1m(exp(log_cdf));
+  }
+};