From 1aef4543ccb3a6e0bc1e51a903898ff06e2bfd04 Mon Sep 17 00:00:00 2001
From: Raj Bhattacharjea <raj.b@gatech.edu>
Date: Fri, 13 Jun 2008 17:19:53 -0700
Subject: [PATCH] bug 181: Normal Variable Infinite Value & Bounds

---
 src/core/random-variable.cc | 26 ++++++++++++++++++++++----
 src/core/random-variable.h  | 26 +++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/src/core/random-variable.cc b/src/core/random-variable.cc
index 336a2a119..778cb2e45 100644
--- a/src/core/random-variable.cc
+++ b/src/core/random-variable.cc
@@ -1043,11 +1043,21 @@ double NormalVariableImpl::GetValue()
         { // Got good pair
           double y = sqrt((-2 * log(w))/w);
           m_next = m_mean + v2 * y * sqrt(m_variance);
-          if (fabs(m_next) > m_bound) m_next = m_bound * (m_next)/fabs(m_next);
-          m_nextValid = true;
+          //if next is in bounds, it is valid
+          m_nextValid = fabs(m_next-m_mean) <= m_bound;
           double x1 = m_mean + v1 * y * sqrt(m_variance);
-          if (fabs(x1) > m_bound) x1 = m_bound * (x1)/fabs(x1);
-          return x1;
+          //if x1 is in bounds, return it
+          if (fabs(x1-m_mean) <= m_bound)
+          {
+            return x1;
+          }
+          //otherwise try and return m_next if it is valid
+          else if (m_nextValid)
+          {
+            m_nextValid = false;
+            return m_next;
+          }
+          //otherwise, just run this loop again
         }
     }
 }
@@ -1094,10 +1104,18 @@ double NormalVariableImpl::GetSingleValue(double m, double v, double b)
 NormalVariable::NormalVariable()
   : RandomVariable (NormalVariableImpl ())
 {}
+NormalVariable::NormalVariable(double m, double v)
+  : RandomVariable (NormalVariableImpl (m, v))
+{}
 NormalVariable::NormalVariable(double m, double v, double b)
   : RandomVariable (NormalVariableImpl (m, v, b))
 {}
 double 
+NormalVariable::GetSingleValue(double m, double v)
+{
+  return NormalVariableImpl::GetSingleValue (m, v);
+}
+double 
 NormalVariable::GetSingleValue(double m, double v, double b)
 {
   return NormalVariableImpl::GetSingleValue (m, v, b);
diff --git a/src/core/random-variable.h b/src/core/random-variable.h
index 4abb36bdb..a311a2bbc 100644
--- a/src/core/random-variable.h
+++ b/src/core/random-variable.h
@@ -490,27 +490,43 @@ public:
 class NormalVariable : public RandomVariable
 {
 public:
-   static const double INFINITE_VALUE;
   /**
    * Constructs an normal random variable  with a mean
    * value of 0 and variance of 1.
    */ 
   NormalVariable();
 
+  /**
+   * \brief Construct a normal random variable with specified mean and variance.
+   * \param m Mean value
+   * \param v Variance
+   */ 
+  NormalVariable(double m, double v);
+
   /**
    * \brief Construct a normal random variable with specified mean and variance
    * \param m Mean value
    * \param v Variance
-   * \param b Bound.  The NormalVariable is bounded within +-bound.
+   * \param b Bound.  The NormalVariable is bounded symetrically about the mean
+   * [mean-bound,mean+bound]
    */ 
-  NormalVariable(double m, double v, double b = INFINITE_VALUE);
+  NormalVariable(double m, double v, double b);
+
   /**
    * \param m Mean value
    * \param v Variance
-   * \param b Bound.  The NormalVariable is bounded within +-bound.
+   * \return A random number from a distribution specified by m, and v.
+   */ 
+  static double GetSingleValue(double m, double v);
+
+  /**
+   * \param m Mean value
+   * \param v Variance
+   * \param b Bound.  The NormalVariable is bounded symetrically about the mean
+   * [mean-bound,mean+bound]
    * \return A random number from a distribution specified by m,v, and b.
    */ 
-  static double GetSingleValue(double m, double v, double b = INFINITE_VALUE);
+  static double GetSingleValue(double m, double v, double b);
 };
 
 /**