#410: util: implement interval set

src/vt/termination/interval/discrete_interval.h

@@ -0,0 +1,353 @@
+/*
+//@HEADER
+// ************************************************************************
+//
+//                          discrete_interval.h
+//                     vt (Virtual Transport)
+//                  Copyright (C) 2018 NTESS, LLC
+//
+// Under the terms of Contract DE-NA-0003525 with NTESS, LLC,
+// the U.S. Government retains certain rights in this software.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// 1. Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the Corporation nor the names of the
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Questions? Contact [email protected]
+//
+// ************************************************************************
+//@HEADER
+*/
+
+#if !defined INCLUDED_VT_TERMINATION_INTERVAL_DISCRETE_INTERVAL_H
+#define INCLUDED_VT_TERMINATION_INTERVAL_DISCRETE_INTERVAL_H
+
+#include "vt/config.h"
+
+#include <algorithm>
+
+namespace vt { namespace term { namespace interval {
+
+/*
+ * Discrete interval tree for encoding non-overlapping integer ranges in a tree
+ */
+
+template <
+  typename DomainT,
+  typename CompareT = std::less<DomainT>,
+  DomainT sentinel = DomainT()
+>
+struct Interval {
+  using IntervalType = Interval<DomainT, CompareT, sentinel>;
+  using DomainType   = DomainT;
+
+  Interval() = default;
+  Interval(Interval const&) = default;
+  Interval(Interval&&) = default;
+  Interval& operator=(Interval const&) = default;
+
+  Interval(DomainT const& val) : lb_(val), ub_(val) { }
+  Interval(DomainT const& lb, DomainT const& ub) : lb_(lb), ub_(ub) { }
+
+public:
+  DomainT lower() const { return lb_; }
+  DomainT upper() const { return ub_; }
+  DomainT width() const { return (ub_-lb_)+1; }
+  bool    valid() const { lb_ <= ub_; }
+
+  template <typename DomainU>
+  bool in(DomainU&& val) const {
+    return val >= lb_ and val <= ub_;
+  }
+
+  void expandBy(DomainT const& val) {
+    if (val > 0) {
+      ub_ += val;
+    } else {
+      lb_ -= val;
+    }
+  }
+
+  enum struct PositionEnum : int {
+    TangentLeft = -1,
+    NotTangent   = 0,
+    TangentRight = 1
+  };
+
+  /*
+   * Determine if a input interval is tangent to this interval within a
+   * specified grap.
+   *
+   *        TangentLeft                   TangentRight
+   *       |------i-----| lb_        ub_ |------i-----|
+   *                      |----this----|
+   *                     ^              ^
+   *                    gap            gap
+   */
+
+  PositionEnum tangent(IntervalType const& i, DomainT gap = 1) {
+    if (lb_ == i.ub_ + gap) {
+      return PositionEnum::TangentLeft;
+    } else if (ub_ == i.lb_ - gap) {
+      return PositionEnum::TangentRight;
+    } else {
+      return PositionEnum::NotTangent;
+    }
+  }
+
+  void join(IntervalType const& i, PositionEnum pos) {
+    switch (pos) {
+    case PositionEnum::TangentLeft:
+      vtAssertExpr(lb_ == i.upper() + 1);
+      lb_ = std::min<DomainT>(lb_, i.lower());
+      break;
+    case PositionEnum::TangentRight:
+      vtAssertExpr(ub_ == i.lower() - 1);
+      ub_ = std::max<DomainT>(ub_, i.upper());
+      break;
+    default:
+      vtAssert(false, "Must have tangent position to join");
+    }
+  }
+
+public:
+  template <typename IntT, typename IntU>
+  static bool less(IntT&& i1, IntU&& i2) {
+    return i1.lower() <= i2.upper() and i2.lower() <= i1.upper();
+  }
+
+  friend bool operator<(IntervalType const& i1, IntervalType const& i2);
+
+private:
+  DomainT lb_ = sentinel;
+  DomainT ub_ = sentinel;
+};
+
+template <typename DomainT, typename CompareT, DomainT sentinel>
+bool operator<(
+  Interval<DomainT, CompareT, sentinel> const& i1,
+  Interval<DomainT, CompareT, sentinel> const& i2
+) {
+  return Interval<DomainT, CompareT, sentinel>::less(i1,i2);
+}
+
+template <typename DomainT>
+struct IntervalCompare {
+  using IntervalType = Interval<DomainT>;
+  bool operator()(IntervalType const& i1, IntervalType const& i2) const {
+    return IntervalType::less(i1,i2);
+  }
+};
+
+
+// template <typename T>
+// struct Node {
+//   template <typename T>
+//   using PtrType = std::unique_ptr<Node<T>>;
+
+//   Node() = default;
+//   explicit Node(T z) : x_(z), y_(z) { }
+
+//   bool inLocal(T z) const { return z >= x_ and z <= y; }
+
+//   bool in(T z) {
+//     if (inLocal(z)) {
+//       return true;
+//     } else {
+//       if (z < x_) {
+//         return c1_ ? c1_->in(z) : false;
+//       } else {
+//         return c2_ ? c2_->in(z) : false;
+//       }
+//     }
+//   }
+
+//   void insert(T z, bool new_insert = false) {
+//     if (inLocal(z)) {
+//       vtAssertInfo(
+//         not new_insert, "Element insertion in interval exists", z, x_, y_
+//       );
+//       return;
+//     }
+
+//     if (z < x_) {
+//       // test expand OR create node
+//       c1_->insert(z);
+//     } else {
+//       // test expand OR create node
+//       c2_->insert(z);
+//     }
+//   }
+
+//   bool hasChildren() const {
+//     return c1 != nullptr or c2 != nullptr;
+//   }
+
+//   void testInvariants() const {
+//     vtAssertExpr(x_ <= y_);
+//   }
+
+// private:
+//   T x_ = 0;
+//   T y_ = 0;
+//   PtrType c1_ = nullptr;
+//   PtrType c2_ = nullptr;
+// };
+
+template <
+  typename DomainT,
+  typename CompareT,
+  template <class, class> class IntervalT,
+  template <class, class> class OrderedSetT
+>
+struct IntervalSetBase {
+  using DomainType          = DomainT;
+  using IntervalType        = IntervalT<DomainT, CompareT>;
+  using IntervalCompareType = IntervalCompare<DomainT>;
+  using OrderedSetType      = OrderedSetT<IntervalType, IntervalCompareType>;
+  using IteratorType        = typename OrderedSetType::iterator;
+  using PositionType        = typename OrderedSetType::PositionEnum;
+
+  IntervalSetBase() : iter_(set_.end()) { }
+  IntervalSetBase(IntervalSetBase const&) = default;
+  IntervalSetBase(IntervalSetBase&&) = default;
+
+  template <
+    typename DomainU,
+    typename = std::enable_if_t<
+      std::is_same<std::remove_reference_t<DomainU>, DomainT>::value
+    >
+  >
+  IteratorType insert(DomainU&& val) {
+    IntervalType i(std::forward<DomainU>(val));
+
+    // Expand the global bounds in this interval set
+    updateGlobal(i);
+
+    return insertSet(iter_,std::move(i));
+  }
+
+  template <
+    typename DomainU,
+    typename = std::enable_if_t<
+      std::is_same<std::remove_reference_t<DomainU>, DomainT>::value
+    >
+  >
+  IteratorType insert(IteratorType it, DomainU&& val) {
+    vtAsserExpr(it not_eq set_.end());
+    IntervalType i(std::forward<DomainU>(val));
+
+    // Expand the global bounds in this interval set
+    updateGlobal(i);
+
+    // If the val is tangent to the hint iterator, directly update
+    auto pos = it->tangent(i);
+    if (pos not_eq PositionType::NotTangent) {
+      it->join(i, pos);
+      return it;
+    }
+
+    return insertSet(it,std::move(i));
+  }
+
+  void clear() {
+    set_.clear();
+    lb_ = ub_ = 0;
+    iter_ = set_.end();
+  }
+
+  DomainT range() const { return ub_ - lb_; }
+  DomainT lower() const { return lb_; }
+  DomainT upper() const { return ub_; }
+  bool    empty() const { return set_.size() == 0; }
+
+private:
+
+  template <
+    typename DomainU,
+    typename = std::enable_if_t<
+      std::is_same<std::remove_reference_t<DomainU>, DomainT>::value
+    >
+  >
+  IteratorType insertSet(IteratorType it, IntervalType i) {
+    // Insert into the set
+    auto ret = set_.emplace_hint(it,std::move(i));
+    vtAssert(ret.second,                  "Should be a valid insert");
+    vtAssert(ret.first not_eq set_.end(), "Must be valid insert---live iterator");
+
+    // Fuse interval set elements that are now tangent after this insertion
+    return iter_ = join(ret.first);
+  }
+
+  void updateGlobal(IntervalType const& i) {
+    // Expand the global bounds in this interval set
+    lb_ = std::min<DomainT>(lb_, i.lower());
+    ub_ = std::max<DomainT>(ub_, i.upper());
+  }
+
+  IteratorType join(IteratorType it) {
+    auto it2 = joinLeft(it);
+    return joinRight(it2);
+  }
+
+  IteratorType joinLeft(IteratorType it) {
+    vtAssertExpr(it not_eq set_.end());
+    if (it not_eq set_.begin()) {
+      auto prev = std::prev(it);
+      if (it->tangent(prev) == PositionType::TangentLeft) {
+        it->join(prev, PositionType::TangentLeft);
+        set_.erase(prev);
+      }
+    }
+    return it;
+  }
+
+  IteratorType joinRight(IteratorType it) {
+    vtAssertExpr(it not_eq set_.end());
+    auto next = std::next(it);
+    if (it not_eq set_.end()) {
+      if (it->tangent(next) == PositionType::TangentRight) {
+        it->join(next, PositionType::TangentRight);
+        set_.erase(next);
+      }
+    }
+    return it;
+  }
+
+private:
+  // The lower bound for the entire set
+  DomainT lb_         = 0;
+  // The upper bound for the entire set
+  DomainT ub_         = 0;
+  // The set of all the interval ranges
+  OrderedSetType set_ = {};
+  // The previous insert iterator for quick lookup
+  IteratorType iter_  = {};
+};
+
+}}} /* end namespace vt::term::interval */
+
+#endif /*INCLUDED_VT_TERMINATION_INTERVAL_DISCRETE_INTERVAL_H*/