Skip to content

Commit

Permalink
other code details
Browse files Browse the repository at this point in the history
  • Loading branch information
@fchapoton
fchapoton committed Jan 31, 2025
1 parent 07517dd commit db52fb0
Showing 1 changed file with 45 additions and 46 deletions.
91 changes: 45 additions & 46 deletions src/sage/combinat/affine_permutation.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -304,7 +304,7 @@ def reduced_word(self):
sage: p.reduced_word()
[0, 7, 4, 1, 0, 7, 5, 4, 2, 1]
"""
#This is about 25% faster than the default algorithm.
# This is about 25% faster than the default algorithm.
x = self
i = 0
word = []
Expand Down Expand Up @@ -409,10 +409,10 @@ def grassmannian_quotient(self, i=0, side='right'):


class AffinePermutationTypeA(AffinePermutation):
#----------------------
#Type-specific methods.
#(Methods existing in all types, but with type-specific definition.)
#----------------------
# ----------------------
# Type-specific methods.
# (Methods existing in all types, but with type-specific definition.)
# ----------------------
def check(self):
r"""
Check that ``self`` is an affine permutation.
Expand Down Expand Up @@ -510,11 +510,11 @@ def apply_simple_reflection_right(self, i):
Type A affine permutation with window [3, -1, 6, 0, 5, 4, 10, 9]
"""
j = i % (self.k+1)
#Cloning is currently kinda broken, in that caches don't clear which
#leads to strangeness with the cloned object.
#The clone approach is quite a bit (2x) faster, though, so this should
#switch once the caching situation is fixed.
#with self.clone(check=False) as l:
# Cloning is currently kinda broken, in that caches don't clear which
# leads to strangeness with the cloned object.
# The clone approach is quite a bit (2x) faster, though, so this should
# switch once the caching situation is fixed.
# with self.clone(check=False) as l:
l = self[:]
if j == 0:
a = l[0]
Expand All @@ -524,7 +524,6 @@ def apply_simple_reflection_right(self, i):
a = l[j-1]
l[j-1] = l[j]
l[j] = a
#return l
return type(self)(self.parent(), l, check=False)

def apply_simple_reflection_left(self, i):
Expand All @@ -539,18 +538,18 @@ def apply_simple_reflection_left(self, i):
sage: p.apply_simple_reflection_left(11)
Type A affine permutation with window [4, -1, 0, 6, 5, 3, 10, 9]
"""
#Here are a couple other methods we tried out, but turned out
#to be slower than the current implementation.
#1) This one was very bad:
# return self.inverse().apply_simple_reflection_right(i).inverse()
#2) Also bad, though not quite so bad:
# return (self.parent().simple_reflection(i))*self
i = i % (self.k+1)
#Cloning is currently kinda broken, in that caches don't clear which
#leads to strangeness with the cloned object.
#The clone approach is quite a bit faster, though, so this should switch
#once the caching situation is fixed.
#with self.clone(check=False) as l:
# Here are a couple other methods we tried out, but turned out
# to be slower than the current implementation.
# 1) This one was very bad:
# return self.inverse().apply_simple_reflection_right(i).inverse()
# 2) Also bad, though not quite so bad:
# return (self.parent().simple_reflection(i))*self
i = i % (self.k + 1)
# Cloning is currently kinda broken, in that caches don't clear which
# leads to strangeness with the cloned object.
# The clone approach is quite a bit faster, though,
# so this should switch once the caching situation is fixed.
# with self.clone(check=False) as l:
l = []
if i != self.k:
for m in range(self.k + 1):
Expand Down Expand Up @@ -627,10 +626,10 @@ def to_type_a(self):
"""
return self

#----------------------
#Type-A-specific methods.
#Only available in Type A.
#----------------------
# ----------------------
# Type-A-specific methods.
# Only available in Type A.
# ----------------------

def flip_automorphism(self):
r"""
Expand Down Expand Up @@ -699,7 +698,7 @@ def maximal_cyclic_factor(self, typ='decreasing', side='right', verbose=False):
else:
descents = self.descents(side='left')
side = 'left'
#for now, assume side is 'right')
# for now, assume side is 'right')
best_T = []
for i in descents:
y = self.clone().apply_simple_reflection(i,side)
Expand Down Expand Up @@ -834,18 +833,18 @@ def to_lehmer_code(self, typ='decreasing', side='right'):
"""
code = [0 for i in range(self.k+1)]
if typ[0] == 'i' and side[0] == 'r':
#Find number of positions to the right of position i with smaller
#value than the number in position i.
# Find number of positions to the right of position i with smaller
# value than the number in position i.
for i in range(self.k+1):
a = self(i)
for j in range(i+1, i+self.k+1):
b = self(j)
if b < a:
code[i] += (a-b) // (self.k+1) + 1
elif typ[0] == 'd' and side[0] == 'r':
#Find number of positions to the left of position i with larger
#value than the number in position i. Then cyclically shift
#the resulting vector.
# Find number of positions to the left of position i with larger
# value than the number in position i. Then cyclically shift
# the resulting vector.
for i in range(self.k+1):
a = self(i)
for j in range(i-self.k, i):
Expand All @@ -855,18 +854,18 @@ def to_lehmer_code(self, typ='decreasing', side='right'):
if a < b:
code[i-1] += ((b-a)//(self.k+1)+1)
elif typ[0] == 'i' and side[0] == 'l':
#Find number of positions to the right of i smaller than i, then
#cyclically shift the resulting vector.
# Find number of positions to the right of i smaller than i, then
# cyclically shift the resulting vector.
for i in range(self.k+1):
pos = self.position(i)
for j in range(pos+1, pos+self.k+1):
b = self(j)
#A small rotation is necessary for the reduced word from
#the lehmer code to match the element.
# A small rotation is necessary for the reduced word from
# the lehmer code to match the element.
if b < i:
code[i-1] += (i-b) // (self.k+1) + 1
elif typ[0] == 'd' and side[0] == 'l':
#Find number of positions to the left of i larger than i.
# Find number of positions to the left of i larger than i.
for i in range(self.k+1):
pos = self.position(i)
for j in range(pos-self.k, pos):
Expand Down Expand Up @@ -1103,7 +1102,7 @@ def value(self, i):
sage: C = AffinePermutationGroup(['C',4,1])
sage: x = C.one()
sage: [x.value(i) for i in range(-10,10)] == list(range(-10,10))
sage: all(x.value(i) == i for i in range(-10,10))
True
"""
N = 2*self.k + 1
Expand All @@ -1124,7 +1123,7 @@ def position(self, i):
sage: C = AffinePermutationGroup(['C',4,1])
sage: x = C.one()
sage: [x.position(i) for i in range(-10,10)] == list(range(-10,10))
sage: all(x.position(i) == i for i in range(-10,10))
True
"""
N = 2*self.k + 1
Expand Down Expand Up @@ -2242,12 +2241,12 @@ def one(self):
True
sage: TestSuite(A).run()
"""
return self(list(range(1, self.k + 2)))
return self(range(1, self.k + 2))

#------------------------
#Type-unique methods.
#(Methods which do not exist in all types.)
#------------------------
# ------------------------
# Type-unique methods.
# (Methods which do not exist in all types.)
# ------------------------
def from_lehmer_code(self, C, typ='decreasing', side='right'):
r"""
Return the affine permutation with the supplied Lehmer code (a weak
Expand Down Expand Up @@ -2353,7 +2352,7 @@ def one(self):
True
sage: TestSuite(C).run()
"""
return self(list(range(1, self.k + 1)))
return self(range(1, self.k + 1))

Element = AffinePermutationTypeC

Expand Down

0 comments on commit db52fb0

Please sign in to comment.