refactor group representation

This commit is contained in:
2019-12-11 21:50:40 -05:00
parent 65077e0312
commit 0917801e97
4 changed files with 269 additions and 198 deletions

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@@ -1,40 +1,66 @@
def cons(it, elem):
yield from it
yield elem
from solver import Group
def ezmults(ngens, rels):
mults = [[2] * ngens for _ in range(ngens)]
def A(n):
""""""
assert 1 <= n
for (f, t), m in rels:
mults[f][t] = m
mults[t][f] = m
for i in range(ngens - 1):
for j in range(i + 1, ngens):
yield ((i, j), mults[i][j])
return Group.schlafli(*[3] * (n - 1))
def schlafli(*mults):
ngens = len(mults) + 1
return ngens, ezmults(ngens, (((i, i + 1), mult) for i, mult in enumerate(mults)))
def B(n):
"""Hypercube Irreducible Coxeter Group"""
assert 2 <= n
return Group.schlafli(4, *[3] * (n - 2))
def torus(n):
return schlafli(n, 2, n)
def D(n):
"""Demicube Irreducible Coxeter Groups"""
assert 4 <= n
def cube(dim):
return schlafli(4, *[3] * (dim - 2))
def icos(dim):
assert 2 <= dim <= 4
return schlafli(5, *[3] * (dim - 2))
g = Group.schlafli(*[3] * (n - 2), 2)
g[1, n - 1] = 3
return g
def E(n):
ngens, mults = schlafli(*[3] * (n - 2), 2)
mults = cons(mults, ((2, n - 1), 3))
return ngens, ezmults(ngens, mults)
"""E_6, E_7, and E_8 Irreducible Coxeter Groups"""
assert 6 <= n <= 8
g = Group.schlafli(*[3] * (n - 2), 2)
g[2, n - 1] = 3
return g
def F4():
"""24-cell Irreducible Coxeter Group"""
return Group.schlafli(3, 4, 3)
def G2():
"""G2 Irreducible Coxeter Group"""
return Group.schlafli(6)
def H(n):
"""Icosahedral Irreducible Coxeter Group"""
assert 2 <= n <= 4
return Group.schlafli(5, *[3] * (n - 2))
def I2(n):
"""Polygon Irreducible Coxeter Groups"""
assert 2 <= n
return Group.schlafli(n)
def T(n):
"""Toroidal Coxeter Group: I_2(n) x I_2(n)"""
assert 2 <= n
return I2(n) ** 2

198
solver.py Normal file
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@@ -0,0 +1,198 @@
from typing import List
def cons(it, elem):
yield from it
yield elem
class Cosets:
def __init__(self, ngens, data=()):
assert len(data) % ngens == 0, 'invalid length starting row'
self.ngens = ngens
self.data = list(data)
self.len = len(data) // ngens
def add_row(self):
self.len += 1
self.data.extend(-1 for _ in range(self.ngens))
def put(self, idx, target):
coset, gen = divmod(idx, self.ngens)
self.data[idx] = target
self.data[target * self.ngens + gen] = coset
def get(self, idx):
return self.data[idx]
def __getitem__(self, key):
coset, gen = key
return self.data[coset * self.ngens + gen]
def __setitem__(self, key, target):
coset, gen = key
self.data[coset * self.ngens + gen] = target
self.data[target * self.ngens + gen] = coset
def __len__(self):
return self.len
def __repr__(self):
return '\n'.join(
f'{i // self.ngens:>3} | ' +
' '.join(
f'{e:>3}' for e in self.data[i:i + self.ngens])
for i in range(0, len(self.data), self.ngens))
class RelTable:
def __init__(self, gens: List[int], mul: int):
self.gens = gens
self.mul = mul
self.fam = []
self.gen = []
self.lst = []
def add_row(self):
idx = len(self.fam)
self.fam.append(-1)
self.gen.append(-1)
self.lst.append(-1)
return idx
class Group:
def __init__(self, ngens, rels=()):
self._mults = [[2] * ngens for _ in range(ngens)]
for (f, t), m in rels:
self._mults[f][t] = m
self._mults[t][f] = m
self.ngens = ngens
@property
def mults(self):
for i in range(self.ngens - 1):
for j in range(i + 1, self.ngens):
yield ((i, j), self._mults[i][j])
def __setitem__(self, key, value):
f, t = key
self._mults[f][t] = value
self._mults[t][f] = value
def __mul__(self, other):
assert isinstance(other, Group)
off = self.ngens
g = Group(self.ngens + other.ngens)
for (i, j), m in self.mults:
g[i, j] = m
for (i, j), m in other.mults:
g[off + i, off + j] = m
return g
def __pow__(self, p, modulo=None):
if modulo is not None: raise NotImplemented
assert isinstance(p, int), 'p must be an integer'
assert p >= 0, 'p must be a nonnegative integer'
g = Group(self.ngens * p)
for (i, j), m in self.mults:
for off in range(0, g.ngens, self.ngens):
g[off + i, off + j] = m
return g
@classmethod
def schlafli(cls, *mults):
ngens = len(mults) + 1
return Group(ngens, (((i, i + 1), mult) for i, mult in enumerate(mults)))
def solve(self, sub_gens=()):
initial_row = [-1] * self.ngens
for s in sub_gens:
initial_row[s] = 0
cosets = Cosets(self.ngens, initial_row)
rel_tables = [RelTable(*a) for a in self.mults]
for rel in rel_tables:
idx = rel.add_row()
count = 0
for g in rel.gens:
if cosets.get(g) == 0:
count += 1
rel.fam[idx] = 0
rel.gen[idx] = 0
rel.lst[idx] = 0
if count == 1:
rel.gen[idx] = -1
idx = 0
while True:
while idx < len(cosets.data) and cosets.get(idx) >= 0:
idx += 1
if idx == len(cosets.data):
break
coset, gen = divmod(idx, cosets.ngens)
target = len(cosets)
cosets.add_row()
for rel in rel_tables:
rel.add_row()
facts = [(coset, gen)]
while facts:
coset, gen = facts.pop()
cosets[coset, gen] = target
for rel in rel_tables:
if gen in rel.gens and rel.fam[target] == -1:
rel.fam[target] = rel.fam[coset]
rel.gen[target] = rel.gen[coset] + 1
if rel.gen[coset] < 0:
rel.gen[target] -= 2
if rel.gen[target] == rel.mul: # forward learn
lst = rel.lst[rel.fam[target]]
gen_ = rel.gens[rel.gens[0] == gen]
facts.append((lst, gen_))
elif rel.gen[target] == -rel.mul: # stationary learn
gen_ = rel.gens[rel.gens[0] == gen]
facts.append((target, gen_))
elif rel.gen[target] == rel.mul - 1:
rel.lst[rel.fam[target]] = target
facts.sort(reverse=True)
for rel in rel_tables:
if rel.fam[target] == -1:
rel.fam[target] = target
rel.gen[target] = 0
count = 0
for g in rel.gens:
if cosets[target, g] == target:
count += 1
if count == 1:
rel.gen[target] = -1
return cosets

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@@ -1,169 +0,0 @@
from typing import List
import groups
class Cosets:
def __init__(self, ngens, data=()):
assert len(data) % ngens == 0, 'invalid length starting row'
self.ngens = ngens
self.data = list(data)
self.len = len(data) // ngens
def add_row(self):
self.len += 1
self.data.extend(-1 for _ in range(self.ngens))
def put(self, idx, target):
coset, gen = divmod(idx, self.ngens)
self.data[idx] = target
self.data[target * self.ngens + gen] = coset
def get(self, idx):
return self.data[idx]
def __getitem__(self, key):
coset, gen = key
return self.data[coset * self.ngens + gen]
def __setitem__(self, key, target):
coset, gen = key
self.data[coset * self.ngens + gen] = target
self.data[target * self.ngens + gen] = coset
def __len__(self):
return self.len
def __repr__(self):
return '\n'.join(
f'{i // self.ngens:>3} | ' +
' '.join(
f'{e:>3}' for e in self.data[i:i + self.ngens])
for i in range(0, len(self.data), self.ngens))
class RelTable:
def __init__(self, gens: List[int], mul: int):
self.gens = gens
self.mul = mul
self.fam = []
self.gen = []
self.lst = []
def add_row(self):
idx = len(self.fam)
self.fam.append(-1)
self.gen.append(-1)
self.lst.append(-1)
return idx
def solve(cosets: Cosets, rel_tables: List[RelTable]):
if len(cosets) < 1:
cosets.add_row()
for rel in rel_tables:
idx = rel.add_row()
count = 0
for g in rel.gens:
if cosets.get(g) == 0:
count += 1
rel.fam[idx] = 0
rel.gen[idx] = 0
rel.lst[idx] = 0
if count == 1:
rel.gen[idx] = -1
idx = 0
while True:
while idx < len(cosets.data) and cosets.get(idx) >= 0:
idx += 1
if idx == len(cosets.data):
break
coset, gen = divmod(idx, cosets.ngens)
target = len(cosets)
cosets.add_row()
for rel in rel_tables:
rel.add_row()
facts = [(coset, gen)]
while facts:
coset, gen = facts.pop()
cosets[coset, gen] = target
for rel in rel_tables:
if gen in rel.gens and rel.fam[target] == -1:
rel.fam[target] = rel.fam[coset]
rel.gen[target] = rel.gen[coset] + 1
if rel.gen[coset] < 0:
rel.gen[target] -= 2
if rel.gen[target] == rel.mul: # forward learn
lst = rel.lst[rel.fam[target]]
gen_ = rel.gens[rel.gens[0] == gen]
facts.append((lst, gen_))
elif rel.gen[target] == -rel.mul: # stationary learn
gen_ = rel.gens[rel.gens[0] == gen]
facts.append((target, gen_))
elif rel.gen[target] == rel.mul - 1:
rel.lst[rel.fam[target]] = target
facts.sort(reverse=True)
for rel in rel_tables:
if rel.fam[target] == -1:
rel.fam[target] = target
rel.gen[target] = 0
count = 0
for g in rel.gens:
if cosets[target, g] == target:
count += 1
if count == 1:
rel.gen[target] = -1
return cosets
def init(ngens, mults, sub_gens=()):
initial_row = [-1] * ngens
for s in sub_gens:
initial_row[s] = 0
cosets = Cosets(ngens, initial_row)
rel_tables = [RelTable(*a) for a in mults]
return cosets, rel_tables
if __name__ == '__main__':
# result = solve(*init_schlafli(5, 3, 3))
# result = solve(*init_schlafli(300, 2, 300))
# group = groups.schlafli(4, 3, 3, 3, 3)
group = groups.icos(4)
import time
s = time.time()
result = solve(*init(*group))
e = time.time()
print(e - s, 's')
print(len(result))
if len(result) < 20:
print(result)
else:
print('--')

16
tests.py Normal file
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@@ -0,0 +1,16 @@
import time
import groups
if __name__ == '__main__':
g = groups.T(100)
s = time.time()
table = g.solve()
e = time.time()
print(f'elapsed = {e - s:.3g}s')
print(len(table))
if len(table) < 20:
print(table)