Real that uses Fast2Sum for addition

[ipdf/code.git] / src / real_fast2sum.h

diff --git a/src/real_fast2sum.h b/src/real_fast2sum.h
new file mode 100644 (file)
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--- /dev/null
+++ b/src/real_fast2sum.h
@@ -0,0 +1,57 @@
+#ifndef _REAL_FAST2SUM_H
+#define _REAL_FAST2SUM_H
+
+#include <cmath>
+// otherwise the abs() function won't work
+
+namespace IPDF
+{
+
+       template <class T = float>
+       struct RealF2S
+       {
+               RealF2S(const T & value = 0.0L) : m_value(value) {} //{Debug("Construct from value %f", m_value);}
+               RealF2S(const RealF2S & cpy) : m_value(cpy.m_value) {} //{Debug("Copy construct from value %f", m_value);}
+
+               RealF2S & operator+=(const RealF2S & a) {this->operator=(RealF2S(*this) + a); return *this;}
+               RealF2S & operator-=(const RealF2S & a) {this->operator=(RealF2S(*this) - a); return *this;}
+               RealF2S & operator*=(const RealF2S & a) {this->operator=(RealF2S(*this) * a); return *this;}
+               RealF2S & operator/=(const RealF2S & a) {this->operator=(RealF2S(*this) / a); return *this;}
+
+               RealF2S & operator=(const RealF2S & equ) {this->m_value = equ.m_value; return *this;}
+               RealF2S & operator=(const T & equ) {this->m_value = equ.m_value; return *this;}
+
+               T m_value;
+       };
+
+       
+
+       template <class T> RealF2S<T> operator+(const RealF2S<T> & a, const RealF2S<T> & b)
+       {
+               // Use fast2sum
+               if (abs(T(a.m_value)) < abs(T(b.m_value)))
+                       return b+a;
+               T z = a.m_value + b.m_value;
+               T w = z - a.m_value;
+               T zz = b.m_value - w;
+               return RealF2S<T>(z + zz);
+       }
+       template <class T> RealF2S<T> operator-(const RealF2S<T> & a, const RealF2S<T> & b)
+       {
+               // Use fast2sum
+               return a + RealF2S<T>(-b.m_value);
+       }
+
+       template <class T> RealF2S<T> operator*(const RealF2S<T> & a, const RealF2S<T> & b)
+       {
+               return RealF2S<T>(a.m_value * b.m_value);
+       }
+       template <class T> RealF2S<T> operator/(const RealF2S<T> & a, const RealF2S<T> & b)
+       {
+               return RealF2S<T>(a.m_value / b.m_value);
+       }
+
+
+}
+
+#endif //_REAL_FAST2SUM_H