diff --git a/graph/DelayFloatClass.cc b/graph/DelayFloatClass.cc
deleted file mode 100644
index d420184e..00000000
--- a/graph/DelayFloatClass.cc
+++ /dev/null
@@ -1,323 +0,0 @@
-// OpenSTA, Static Timing Analyzer
-// Copyright (c) 2018, Parallax Software, Inc.
-// 
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-// 
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-// 
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-#include "Machine.hh"
-#include "Fuzzy.hh"
-#include "Units.hh"
-#include "StaState.hh"
-#include "Delay.hh"
-
-// Conditional compilation based on delay abstraction from Delay.hh.
-#ifdef DELAY_FLOAT_CLASS
-
-namespace sta {
-
-static Delay delay_init_values[MinMax::index_count];
-
-void
-initDelayConstants()
-{
-  delay_init_values[MinMax::minIndex()] = MinMax::min()->initValue();
-  delay_init_values[MinMax::maxIndex()] = MinMax::max()->initValue();
-}
-
-const Delay &
-delayInitValue(const MinMax *min_max)
-{
-  return delay_init_values[min_max->index()];
-}
-
-Delay::Delay() :
-  delay_(0.0)
-{
-}
-
-Delay::Delay(float delay) :
-  delay_(delay)
-{
-}
-
-void
-Delay::operator=(const Delay &delay)
-{
-  delay_ = delay.delay_;
-}
-
-void
-Delay::operator=(float delay)
-{
-  delay_ = delay;
-}
-
-void
-Delay::operator+=(const Delay &delay)
-{
-  delay_ += delay.delay_;
-}
-
-void
-Delay::operator+=(float delay)
-{
-  delay_ += delay;
-}
-
-Delay
-Delay::operator+(const Delay &delay) const
-{
-  return Delay(delay_ + delay.delay_);
-}
-
-Delay
-Delay::operator+(float delay) const
-{
-  return Delay(delay_ + delay);
-}
-
-Delay
-Delay::operator-(const Delay &delay) const
-{
-  return Delay(delay_ - delay.delay_);
-}
-
-Delay
-Delay::operator-(float delay) const
-{
-  return Delay(delay_ - delay);
-}
-
-Delay
-Delay::operator-() const
-{
-  return Delay(-delay_);
-}
-
-void
-Delay::operator-=(float delay)
-{
-  delay_ -= delay;
-}
-
-bool
-Delay::operator==(const Delay &delay) const
-{
-  return delay_ == delay.delay_;
-}
-
-bool
-Delay::operator>(const Delay &delay) const
-{
-  return delay_ > delay.delay_;
-}
-
-bool
-Delay::operator>=(const Delay &delay) const
-{
-  return delay_ >= delay.delay_;
-}
-
-bool
-Delay::operator<(const Delay &delay) const
-{
-  return delay_ < delay.delay_;
-}
-
-bool
-Delay::operator<=(const Delay &delay) const
-{
-  return delay_ <= delay.delay_;
-}
-
-bool
-delayIsInitValue(const Delay &delay,
-		 const MinMax *min_max)
-{
-  return fuzzyEqual(delayAsFloat(delay), min_max->initValue());
-}
-
-bool
-delayFuzzyZero(const Delay &delay)
-{
-  return fuzzyZero(delayAsFloat(delay));
-}
-
-bool
-delayFuzzyEqual(const Delay &delay1,
-		const Delay &delay2)
-{
-  return fuzzyEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyLess(const Delay &delay1,
-	       const Delay &delay2)
-{
-  return fuzzyLess(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyLess(const Delay &delay1,
-	       float delay2)
-{
-  return fuzzyLess(delayAsFloat(delay1), delay2);
-}
-
-bool
-delayFuzzyLessEqual(const Delay &delay1,
-		    const Delay &delay2)
-{
-  return fuzzyLessEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyLessEqual(const Delay &delay1,
-		    float delay2)
-{
-  return fuzzyLessEqual(delayAsFloat(delay1), delay2);
-}
-
-bool
-delayFuzzyLessEqual(const Delay &delay1,
-		    const Delay &delay2,
-		    const MinMax *min_max)
-{
-  if (min_max == MinMax::max())
-    return fuzzyLessEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-  else
-    return fuzzyGreaterEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyGreater(const Delay &delay1,
-		  const Delay &delay2)
-{
-  return fuzzyGreater(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyGreater(const Delay &delay1,
-		  float delay2)
-{
-  return fuzzyGreater(delayAsFloat(delay1), delay2);
-}
-
-bool
-delayFuzzyGreaterEqual(const Delay &delay1,
-		       const Delay &delay2)
-{
-  return fuzzyGreaterEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyGreaterEqual(const Delay &delay1,
-		       float delay2)
-{
-  return fuzzyGreaterEqual(delayAsFloat(delay1), delay2);
-}
-
-bool
-delayFuzzyGreater(const Delay &delay1,
-		  const Delay &delay2,
-		  const MinMax *min_max)
-{
-  if (min_max == MinMax::max())
-    return fuzzyGreater(delayAsFloat(delay1), delayAsFloat(delay2));
-  else
-    return fuzzyLess(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyGreaterEqual(const Delay &delay1,
-		       const Delay &delay2,
-		       const MinMax *min_max)
-{
-  if (min_max == MinMax::max())
-    return fuzzyGreaterEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-  else
-    return fuzzyLessEqual(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-bool
-delayFuzzyLess(const Delay &delay1,
-	       const Delay &delay2,
-	       const MinMax *min_max)
-{
-  if (min_max == MinMax::max())
-    return fuzzyLess(delayAsFloat(delay1), delayAsFloat(delay2));
-  else
-    return fuzzyGreater(delayAsFloat(delay1), delayAsFloat(delay2));
-}
-
-Delay
-operator+(float delay1,
-	  const Delay &delay2)
-{
-  return Delay(delay1 + delayAsFloat(delay2));
-}
-
-Delay
-operator-(float delay1,
-	  const Delay &delay2)
-{
-  return Delay(delay1 - delayAsFloat(delay2));
-}
-
-Delay
-operator/(float delay1,
-	  const Delay &delay2)
-{
-  return Delay(delay1 / delayAsFloat(delay2));
-}
-
-Delay
-operator*(const Delay &delay1,
-	  float delay2)
-{
-  return Delay(delayAsFloat(delay1) * delay2);
-}
-
-float
-delayRatio(const Delay &delay1,
-	   const Delay &delay2)
-{
-  return delayAsFloat(delay1) / delayAsFloat(delay2);
-}
-
-const char *
-delayAsString(const Delay &delay,
-	      const Units *units,
-	      int digits)
-{
-  return units->timeUnit()->asString(delay.delay(), digits);
-}
-
-float
-delayMeanSigma(const Delay &delay,
-	       const EarlyLate *)
-{
-  return delay.delay();
-}
-
-const char *
-delayMeanSigmaString(const Delay &delay,
-		     const EarlyLate *,
-		     const Units *units,
-		     int digits)
-{
-  return units->timeUnit()->asString(delay.delay(), digits);
-}
-
-} // namespace
-#endif
diff --git a/graph/DelayFloatClass.hh b/graph/DelayFloatClass.hh
deleted file mode 100644
index 028ebd64..00000000
--- a/graph/DelayFloatClass.hh
+++ /dev/null
@@ -1,98 +0,0 @@
-// OpenSTA, Static Timing Analyzer
-// Copyright (c) 2018, Parallax Software, Inc.
-// 
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-// 
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-// 
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-#ifndef STA_DELAY_FLOAT_CLASS_H
-#define STA_DELAY_FLOAT_CLASS_H
-
-#include "MinMax.hh"
-
-namespace sta {
-
-// Delay values defined as class objects that hold a float value.
-// This is really a trial balloon for delay values as objects
-// instead of simple floats.
-
-class Delay
-{
-public:
-  Delay();
-  Delay(float delay);
-  float delay() const { return delay_; }
-  void operator=(const Delay &delay);
-  void operator=(float delay);
-  void operator+=(const Delay &delay);
-  void operator+=(float delay);
-  Delay operator+(const Delay &delay) const;
-  Delay operator+(float delay) const;
-  Delay operator-(const Delay &delay) const;
-  Delay operator-(float delay) const;
-  Delay operator-() const;
-  void operator-=(float delay);
-  bool operator==(const Delay &delay) const;
-  bool operator>(const Delay &delay) const;
-  bool operator>=(const Delay &delay) const;
-  bool operator<(const Delay &delay) const;
-  bool operator<=(const Delay &delay) const;
-
-private:
-  float delay_;
-};
-
-const Delay delay_zero(0.0);
-
-inline Delay
-makeDelay(float delay,
-	  float,
-	  float)
-{
-  return Delay(delay);
-}
-
-inline float
-delayAsFloat(const Delay &delay) { return delay.delay(); }
-
-// Most non-operator functions on Delay are not defined as member
-// functions so they can be defined on floats, where there is no class
-// to define them.
-
-Delay operator+(float delay1,
-		const Delay &delay2);
-Delay operator-(float delay1,
-		const Delay &delay2);
-// Used for parallel gate delay calc.
-Delay operator/(float delay1,
-		const Delay &delay2);
-// Used for parallel gate delay calc.
-Delay operator*(const Delay &delay2,
-		float delay1);
-Delay operator*(const Delay &delay1,
-		float delay2);
-
-bool
-delayFuzzyLess(const Delay &delay1,
-	       float delay2);
-bool
-delayFuzzyLessEqual(const Delay &delay1,
-		    float delay2);
-bool
-delayFuzzyGreater(const Delay &delay1,
-		  float delay2);
-bool
-delayFuzzyGreaterEqual(const Delay &delay1,
-		       float delay2);
-
-} // namespace
-#endif