def hz2hx(self, i=0, j=0):
Lx, Lz, Hx, Tz, Hz, Tx = (
self.Lx, self.Lz, self.Hx,
self.Tz, self.Hz, self.Tx)
opx, opz = Tx[i], Hz[i]
self.Tx, self.Hz = pop2(Tx, i), pop2(Hz, i)
self.Hx, self.Tz = insert2(Hx, j, opx), insert2(Tz, j, opz)
self.mz -= 1
self.mx += 1
self.do_check()
def hx2hz(self, i=0, j=0):
Lx, Lz, Hx, Tz, Hz, Tx = (
self.Lx, self.Lz, self.Hx,
self.Tz, self.Hz, self.Tx)
opx, opz = Hx[i], Tz[i]
self.Hx, self.Tz = pop2(Hx, i), pop2(Tz, i)
self.Tx, self.Hz = insert2(Tx, j, opx), insert2(Hz, j, opz)
self.mz += 1
self.mx -= 1
self.do_check()
def logop2hz(self, i=0, j=0):
"move the i-th z type logical operator into Hz"
Lx, Lz, Hx, Tz, Hz, Tx = (
self.Lx, self.Lz, self.Hx,
self.Tz, self.Hz, self.Tx)
lx, lz = Lx[i], Lz[i]
self.Lx, self.Lz = pop2(Lx, i), pop2(Lz, i)
self.Tx, self.Hz = insert2(Tx, j, lx), insert2(Hz, j, lz)
self.k -= 1
self.mz += 1
self.do_check()
def stabweights(U, L, verbose=False):
U = U.copy()
L = L.copy()
# Shorten stabilizers -------------
n = U.shape[0]
m = n//2
Hz, Tz = U[:m], U[m:]
Tx, Hx = L[:m], L[m:]
# print shortstrx(Hx, Hz)
#Lx, Lz = zeros2(0, n), zeros2(0, n)
#code = CSSCode(Lx, Lz, Hx, Tz, Hz, Tx, build=False)
#print code
#print code.weightstr()
ws = []
for i in range(m):
Hz1 = pop2(Hz, i)
graph = Tanner(Hz1)
#write("i=%d w=%d "%(i, Lz[i].sum()))
op = graph.localmin(Hz[i], verbose=verbose)
if op.sum() < Hz[i].sum():
Hz[i] = op
write('.')
else:
write(choice('\/'))
ws.append(op.sum())
for i in range(m):
Hx1 = pop2(Hx, i)
graph = Tanner(Hx1)
#write("i=%d w=%d "%(i, Lx[i].sum()))
op = graph.localmin(Hx[i], verbose=verbose)
if op.sum() < Hx[i].sum():
Hx[i] = op
write('.')
else:
write(choice('\/'))
ws.append(op.sum())
# print ws
# print shortstrx(Hx, Hz)
return ws
code = CSSCode(Lx, Lz, Hx, None, Hz, None, build=False)
print(code)
print(code.weightstr())
return code
def hpack(n, j=4, k=1, check=True, verbose=False):
write("hpack...")
U = identity2(n) # upper triangular
L = identity2(n) # lower triangular
I = identity2(n)
for count in range(j*n):
i = randint(0, n-1)
j = randint(0, n-1)
if i==j:
continue
U[i] = (U[i] + U[j])%2
L[j] = (L[j] - L[i])%2
assert solve.rank(U) == n
assert solve.rank(L) == n
assert eq2(dot2(U, L.transpose()), I)
if verbose:
print()
print(shortstrx(U, L))
print()
ws = [n] * n
ws = stabweights(U, L)
for i in range(n):
w = min(U[i].sum(), L[i].sum())
ws[i] = min(ws[i], w)
ws = list(enumerate(ws))
ws.sort(key = lambda item : -item[1])
idxs = [ws[i][0] for i in range(k)]
idxs.sort()
Lx, Lz = zeros2(0, n), zeros2(0, n)
for idx in reversed(idxs):
Lz = append2(Lz, U[idx:idx+1])
Lx = append2(Lx, L[idx:idx+1])
U = pop2(U, idx)
L = pop2(L, idx)
m = (n-k)//2
Hz, Tz = U[:m], U[m:]
Tx, Hx = L[:m], L[m:]
if verbose:
print()
print(shortstrx(Hx, Hz))
write("done.\n")
code = CSSCode(Lx, Lz, Hx, Tz, Hz, Tx, check=check, verbose=verbose)
return code