From 2d20cd31f25c3949218dbb9a3a6350be5c961319 Mon Sep 17 00:00:00 2001
From: "Paul P.H. Wilson" <paul.wilson@wisc.edu>
Date: Thu, 16 Mar 2023 14:37:05 -0500
Subject: [PATCH] initialize Discrete distribution with sequence of integers

---
 include/openmc/distribution.h |  1 +
 src/distribution.cpp          | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/openmc/distribution.h b/include/openmc/distribution.h
index 815ffa21a5..86aa4a3819 100644
--- a/include/openmc/distribution.h
+++ b/include/openmc/distribution.h
@@ -39,6 +39,7 @@ class Discrete : public Distribution {
 public:
   explicit Discrete(pugi::xml_node node);
   Discrete(const double* x, const double* p, int n);
+  Discrete(const double* p, int n);
 
   //! Sample a value from the distribution
   //! \param seed Pseudorandom number seed pointer
diff --git a/src/distribution.cpp b/src/distribution.cpp
index 4b4ebd69d7..ce2a85705c 100644
--- a/src/distribution.cpp
+++ b/src/distribution.cpp
@@ -41,6 +41,19 @@ Discrete::Discrete(const double* x, const double* p, int n)
   this->init_alias(x_vec, p_vec);
 }
 
+Discrete::Discrete(const double* p, int n)
+{
+  std::vector<double> p_vec(p, p + n);
+  std::vector<double> x_vec(n);
+
+  for (int i=0; i<n; i++) 
+  {
+    x_vec[i] = i;
+  }
+
+  this->init_alias(x_vec, p_vec);
+}
+
 void Discrete::init_alias(vector<double>& x, vector<double>& p)
 {
   x_ = x;