def sum_columns(m):
v = CuckooVector({})
for key,col in m.columns():
v.add(col)
return v
def power_iteration(m, iterations, v0):
v = CuckooVector({})
v.add(v0)
for i in range(iterations):
v = m.mult_vec(v)
mu = v.norm(2)
v.scale(1.0/mu)
return mu,v
def power_iteration_mmt(m, iterations, v0):
v = CuckooVector({})
v.add(v0)
for i in range(iterations):
vp = CuckooVector({})
for c in m:
vp.add_scale(c, c.dot(v))
mu = vp.norm(2)
vp.scale(1.0/mu)
v = vp
return mu,v
def power_iteration_4(Y, X, U, S, iterations, v0):
v = CuckooVector({})
v.add(v0)
for i in range(iterations):
v1 = CuckooVector({})
for (x,y) in zip(X,Y):
v1.add_scale_dict(x, v.dot_dict(y))
v2 = CuckooVector({})
for (x,y) in zip(X,Y):
v2.add_scale_dict(y, v1.dot_dict(x))
for (u,s) in zip(U,S):
print(-s * u.dot(v))
v2.add_scale(u, -s * u.dot(v))
mu = v2.norm(2)
v2.scale(1.0/mu)
v = v2
return mu,v
