OpenSTA/util/Fuzzy.cc

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2026, 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/>.
// 
// The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software.
// 
// Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 
// This notice may not be removed or altered from any source distribution.

#include "Fuzzy.hh"

#include <algorithm> // max
#include <cmath> // abs

#include "MinMax.hh" // INF

namespace sta {

constexpr static float float_equal_tolerance = 1E-15F;

bool
fuzzyEqual(float v1,
           float v2)
{
  if (v1 == v2)
    return true;
  else if (v1 == 0.0)
    return std::abs(v2) < float_equal_tolerance;
  else if (v2 == 0.0)
    return std::abs(v1) < float_equal_tolerance;
  else
    return std::abs(v1 - v2) < 1E-6F * std::max(std::abs(v1), std::abs(v2));
}

bool
fuzzyZero(float v)
{
  return v == 0.0
    || std::abs(v) < float_equal_tolerance;
}

bool
fuzzyLess(float v1,
          float v2)
{
  return v1 < v2 && !fuzzyEqual(v1, v2);
}

bool
fuzzyLessEqual(float v1,
               float v2)
{
  return v1 < v2 || fuzzyEqual(v1, v2);
}

bool
fuzzyGreater(float v1,
             float v2)
{
  return v1 > v2 && !fuzzyEqual(v1, v2);
}

bool
fuzzyGreaterEqual(float v1,
                  float v2)
{
  return v1 > v2 || fuzzyEqual(v1, v2);
}

bool
fuzzyInf(float value)
{
  return fuzzyEqual(value, INF)
    || fuzzyEqual(value, -INF);
}

} // namespace sta