/usr/lib/python3/dist-packages/ufl/exprequals.py is in python3-ufl 2017.2.0.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | # -*- coding: utf-8 -*-
from collections import defaultdict
from six.moves import zip
from ufl.core.expr import Expr
from ufl.log import error
hash_total = defaultdict(int)
hash_collisions = defaultdict(int)
hash_equals = defaultdict(int)
hash_notequals = defaultdict(int)
def print_collisions():
keys = sorted(hash_total.keys(), key=lambda x: (hash_collisions[x], x))
print("Collision statistics ({0} keys):".format(len(keys)))
print("[key: equals; notequals; collisions]")
n = max(len(str(k)) for k in keys)
fmt = ("%%%ds" % n) + ": \t %6d (%3d%%); %6d (%3d%%); %6d (%3d%%) col; tot %d"
for k in keys:
co = hash_collisions[k]
eq = hash_equals[k]
ne = hash_notequals[k]
tot = hash_total[k]
sn, on = k
# Skip those that are all not equal
if sn != on and ne == tot:
continue
print(fmt % (k, eq, int(100.0*eq/tot),
ne, int(100.0*ne/tot),
co, int(100.0*co/tot),
tot))
def measure_collisions(equals_func):
def equals_func_with_collision_measuring(self, other):
# Call equals
equal = equals_func(self, other)
# Get properties
st = type(self)
ot = type(other)
sn = st.__name__
on = ot.__name__
sh = hash(self)
oh = hash(other)
key = (sn, on)
# If hashes are the same but objects are not equal, we have a
# collision
hash_total[key] += 1
if sh == oh and not equal:
hash_collisions[key] += 1
elif sh != oh and equal:
error("Equal objects must always have the same hash! Objects are:\n{0}\n{1}".format(self, other))
elif sh == oh and equal:
hash_equals[key] += 1
elif sh != oh and not equal:
hash_notequals[key] += 1
return equal
return equals_func_with_collision_measuring
# @measure_collisions
def recursive_expr_equals(self, other): # Much faster than the more complex algorithms above!
"""Checks whether the two expressions are represented the
exact same way. This does not check if the expressions are
mathematically equal or equivalent! Used by sets and dicts."""
# To handle expr == int/float
if not isinstance(other, Expr):
return False
# Fast cutoff for common case
if self._ufl_typecode_ != other._ufl_typecode_:
return False
# Compare hashes, will cutoff more or less all nonequal types
if hash(self) != hash(other):
return False
# Large objects are costly to compare with themselves
if self is other:
return True
# Terminals
if self._ufl_is_terminal_:
# Compare terminals with custom == to capture subclass
# overloading of __eq__
return self == other
# --- Operators, most likely equal, below here is the costly part
# --- if it recurses through a large tree! ---
# Recurse manually to call expr_equals directly without the class
# EQ overhead!
equal = all(recursive_expr_equals(a, b) for (a, b) in zip(self.ufl_operands,
other.ufl_operands))
return equal
# @measure_collisions
def nonrecursive_expr_equals(self, other):
"""Checks whether the two expressions are represented the
exact same way. This does not check if the expressions are
mathematically equal or equivalent! Used by sets and dicts."""
# Fast cutoffs for common cases, type difference or hash
# difference will cutoff more or less all nonequal types
if type(self) != type(other) or hash(self) != hash(other):
return False
# Large objects are costly to compare with themselves
if self is other:
return True
# Modelled after pre_traversal to avoid recursion:
left = [(self, other)]
while left:
s, o = left.pop()
if s._ufl_is_terminal_:
# Compare terminals
if not s == o:
return False
else:
# Delve into subtrees
so = s.ufl_operands
oo = o.ufl_operands
if len(so) != len(oo):
return False
for s, o in zip(so, oo):
# Fast cutoff for common case
if s._ufl_typecode_ != o._ufl_typecode_:
return False
# Skip subtree if objects are the same
if s is o:
continue
# Append subtree for further inspection
left.append((s, o))
# Equal if we get out of the above loop!
return True
# expr_equals = recursive_expr_equals
expr_equals = nonrecursive_expr_equals
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