def _distributive(self):
if self.type in __distributions:
star = __distributions[self.type]
extracted = []
factorList = Counter()
def _pushToExtracted(child, count):
assert count == 1
extracted.append(child)
factorList.update(keysExcept(child.children,
Expression.isConstant))
(rest, hasStar) = performIf(self.children, Expression.isType(star),
_pushToExtracted)
if hasStar:
# Algorithm for factorization:
#
# 1. find the most common factor
# 2. check if that factor has appeared >1 times. If no, quit.
# 3. otherwise, scan for all children which contain that factor.
# 4. remove that factor from those children, and create a new
# a*(b+c+d) style expression.
factorizedOnce = False
while factorList:
(commonest, count) = factorList.most_common(1)[0]
if count == 1:
if factorizedOnce:
rest.update(extracted)
return self.replaceChildren(rest)
else:
return None
else:
factorizedOnce = True
oldExtracted = extracted
extracted = []
newChildrenList = []
for child in oldExtracted:
if commonest in child.children:
factorList.subtract(
keysExcept(child.children,
Expression.isConstant))
newChildChildren = Counter(child.children)
newChildChildren[commonest] -= 1
newChild = child.replaceChildren(newChildChildren)
newChildrenList.append(newChild)
else:
extracted.append(child)
newExpression = Expression(
star, commonest, Expression(self.type,
*newChildrenList))
extracted.append(newExpression)
factorList.update(
keysExcept(child.children, Expression.isConstant))
def _distributive(self):
if self.type in __distributions:
star = __distributions[self.type]
extracted = []
factorList = Counter()
def _pushToExtracted(child, count):
assert count == 1
extracted.append(child)
factorList.update(
keysExcept(child.children, Expression.isConstant))
(rest, hasStar) = performIf(self.children, Expression.isType(star),
_pushToExtracted)
if hasStar:
# Algorithm for factorization:
#
# 1. find the most common factor
# 2. check if that factor has appeared >1 times. If no, quit.
# 3. otherwise, scan for all children which contain that factor.
# 4. remove that factor from those children, and create a new
# a*(b+c+d) style expression.
factorizedOnce = False
while factorList:
(commonest, count) = factorList.most_common(1)[0]
if count == 1:
if factorizedOnce:
rest.update(extracted)
return self.replaceChildren(rest)
else:
return None
else:
factorizedOnce = True
oldExtracted = extracted
extracted = []
newChildrenList = []
for child in oldExtracted:
if commonest in child.children:
factorList.subtract(
keysExcept(child.children,
Expression.isConstant))
newChildChildren = Counter(child.children)
newChildChildren[commonest] -= 1
newChild = child.replaceChildren(newChildChildren)
newChildrenList.append(newChild)
else:
extracted.append(child)
newExpression = Expression(
star, commonest, Expression(self.type,
*newChildrenList))
extracted.append(newExpression)
factorList.update(
keysExcept(child.children, Expression.isConstant))
def _pushToExtracted(child, count):
assert count == 1
extracted.append(child)
factorList.update(keysExcept(child.children,
Expression.isConstant))
def _pushToExtracted(child, count): assert count == 1 extracted.append(child) factorList.update(keysExcept(child.children, Expression.isConstant))