old_contents: # Copyright 2017, Google Inc.
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #     * Redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer.
  #     * 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.
  #     * Neither the name of Google Inc. nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "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 THE COPYRIGHT
  # OWNER OR 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.
  
  from scipy import stats
  import math
  
  _DEFAULT_THRESHOLD = 1e-10
  
  def scale(a, mul):
    return [x * mul for x in a]
  
  
  def cmp(a, b):
    return stats.ttest_ind(a, b)
  
  def speedup(new, old, threshold = _DEFAULT_THRESHOLD):
    if (len(set(new))) == 1 and new == old: return 0
    s0, p0 = cmp(new, old)
    if math.isnan(p0): return 0
    if s0 == 0: return 0
    if p0 > _DEFAULT_THRESHOLD: return 0
    if s0 < 0:
      pct = 1
      while pct < 100:
        sp, pp = cmp(new, scale(old, 1 - pct / 100.0))
        if sp > 0: break
        if pp > _DEFAULT_THRESHOLD: break
        pct += 1
      return -(pct - 1)
    else:
      pct = 1
      while pct < 10000:
        sp, pp = cmp(new, scale(old, 1 + pct / 100.0))
        if sp < 0: break
        if pp > _DEFAULT_THRESHOLD: break
        pct += 1
      return pct - 1
  
  
  if __name__ == "__main__":
    new = [0.0, 0.0, 0.0, 0.0] 
    old = [2.96608e-06, 3.35076e-06, 3.45384e-06, 3.34407e-06]
    print speedup(new, old, 1e-5)
    print speedup(old, new, 1e-5)
  
new_contents: # Copyright 2017, Google Inc.
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #     * Redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer.
  #     * 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.
  #     * Neither the name of Google Inc. nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "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 THE COPYRIGHT
  # OWNER OR 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.
  
  from scipy import stats
  import math
  
  _DEFAULT_THRESHOLD = 1e-10
  
  def scale(a, mul):
    return [x * mul for x in a]
  
  
  def cmp(a, b):
    return stats.ttest_ind(a, b)
  
  def speedup(new, old, threshold = _DEFAULT_THRESHOLD):
    if (len(set(new))) == 1 and new == old: return 0
    s0, p0 = cmp(new, old)
    if math.isnan(p0): return 0
    if s0 == 0: return 0
    if p0 > threshold: return 0
    if s0 < 0:
      pct = 1
      while pct < 100:
        sp, pp = cmp(new, scale(old, 1 - pct / 100.0))
        if sp > 0: break
        if pp > threshold: break
        pct += 1
      return -(pct - 1)
    else:
      pct = 1
      while pct < 10000:
        sp, pp = cmp(new, scale(old, 1 + pct / 100.0))
        if sp < 0: break
        if pp > threshold: break
        pct += 1
      return pct - 1
  
  
  if __name__ == "__main__":
    new = [0.0, 0.0, 0.0, 0.0] 
    old = [2.96608e-06, 3.35076e-06, 3.45384e-06, 3.34407e-06]
    print speedup(new, old, 1e-5)
    print speedup(old, new, 1e-5)
  
subject: Fix bm_speedup