def remove_redundant_rows(data):
"""Remove redundant constraints from A and G.
Parameters
----------
data : dict
All the problem data.
Returns
-------
str
A status indicating if infeasibility was detected.
"""
# Extract data.
dims = data[s.DIMS]
A = data[s.A]
G = data[s.G]
b = data[s.B]
h = data[s.H]
# Remove redundant rows in A.
if A.shape[0] > 0:
# The pivoting improves robustness.
Q, R, P = scipy.linalg.qr(A.todense(), pivoting=True)
rows_to_keep = []
for i in range(R.shape[0]):
if np.linalg.norm(R[i, :]) > 1e-10:
rows_to_keep.append(i)
R = R[rows_to_keep, :]
Q = Q[:, rows_to_keep]
# Invert P from col -> var to var -> col.
Pinv = np.zeros(P.size, dtype='int')
for i in range(P.size):
Pinv[P[i]] = i
# Rearrage R.
R = R[:, Pinv]
A = R
b_old = b
b = Q.T.dot(b)
# If b is not in the range of Q,
# the problem is infeasible.
if not np.allclose(b_old, Q.dot(b)):
return s.INFEASIBLE
dims[s.EQ_DIM] = int(b.shape[0])
data["Q"] = intf.dense2cvxopt(Q)
# Remove obviously redundant rows in G's <= constraints.
if dims[s.LEQ_DIM] > 0:
G = G.tocsr()
G_leq = G[:dims[s.LEQ_DIM], :]
h_leq = h[:dims[s.LEQ_DIM]].ravel()
G_other = G[dims[s.LEQ_DIM]:, :]
h_other = h[dims[s.LEQ_DIM]:].ravel()
G_leq, h_leq, P_leq = compress_matrix(G_leq, h_leq)
dims[s.LEQ_DIM] = int(h_leq.shape[0])
data["P_leq"] = intf.sparse2cvxopt(P_leq)
G = sp.vstack([G_leq, G_other])
h = np.hstack([h_leq, h_other])
# Convert A, b, G, h to CVXOPT matrices.
data[s.A] = A
data[s.G] = G
data[s.B] = b
data[s.H] = h
return s.OPTIMAL
def remove_redundant_rows(data):
"""Remove redundant constraints from A and G.
Parameters
----------
data : dict
All the problem data.
Returns
-------
str
A status indicating if infeasibility was detected.
"""
dims = data[s.DIMS]
# Convert A, b, G, h to scipy sparse matrices and numpy 1D arrays.
A = intf.DEFAULT_SPARSE_INTF.const_to_matrix(data[s.A],
convert_scalars=True)
G = intf.DEFAULT_SPARSE_INTF.const_to_matrix(data[s.G],
convert_scalars=True)
b = intf.DEFAULT_NP_INTF.const_to_matrix(data[s.B],
convert_scalars=True)
h = intf.DEFAULT_NP_INTF.const_to_matrix(data[s.H],
convert_scalars=True)
# Remove redundant rows in A.
if A.shape[0] > 0:
# The pivoting improves robustness.
Q, R, P = scipy.linalg.qr(A.todense(), pivoting=True)
rows_to_keep = []
for i in range(R.shape[0]):
if np.linalg.norm(R[i,:]) > 1e-10:
rows_to_keep.append(i)
R = R[rows_to_keep,:]
Q = Q[:, rows_to_keep]
# Invert P from col -> var to var -> col.
Pinv = np.zeros(P.size, dtype='int')
for i in range(P.size):
Pinv[P[i]] = i
# Rearrage R.
R = R[:,Pinv]
A = R
b_old = b
b = Q.T.dot(b)
# If b is not in the range of Q,
# the problem is infeasible.
if not np.allclose(b_old, Q.dot(b)):
return s.INFEASIBLE
dims[s.EQ_DIM] = b.shape[0]
data["Q"] = intf.CVXOPT_DENSE_INTF.const_to_matrix(Q,
convert_scalars=True)
# Remove obviously redundant rows in G's <= constraints.
if dims[s.LEQ_DIM] > 0:
G = G.tocsr()
G_leq = G[:dims[s.LEQ_DIM],:]
h_leq = h[:dims[s.LEQ_DIM]]
G_other = G[dims[s.LEQ_DIM]:,:]
h_other = h[dims[s.LEQ_DIM]:]
G_leq, h_leq, P_leq = compress_matrix(G_leq, h_leq)
dims[s.LEQ_DIM] = h_leq.shape[0]
data["P_leq"] = intf.CVXOPT_SPARSE_INTF.const_to_matrix(P_leq,
convert_scalars=True)
# Scipy 0.13 can't stack empty arrays.
if G_leq.shape[0] > 0 and G_other.shape[0] > 0:
G = sp.vstack([G_leq, G_other])
elif G_leq.shape[0] > 0:
G = G_leq
else:
G = G_other
h = np.vstack([h_leq, h_other])
# Convert A, b, G, h to CVXOPT matrices.
data[s.A] = intf.CVXOPT_SPARSE_INTF.const_to_matrix(A,
convert_scalars=True)
data[s.G] = intf.CVXOPT_SPARSE_INTF.const_to_matrix(G,
convert_scalars=True)
data[s.B] = intf.CVXOPT_DENSE_INTF.const_to_matrix(b,
convert_scalars=True)
data[s.H] = intf.CVXOPT_DENSE_INTF.const_to_matrix(h,
convert_scalars=True)
return s.OPTIMAL
def remove_redundant_rows(data):
"""Remove redundant constraints from A and G.
Parameters
----------
data : dict
All the problem data.
Returns
-------
str
A status indicating if infeasibility was detected.
"""
# Extract data.
dims = data[s.DIMS]
A = data[s.A]
G = data[s.G]
b = data[s.B]
h = data[s.H]
# Remove redundant rows in A.
if A.shape[0] > 0:
# The pivoting improves robustness.
Q, R, P = scipy.linalg.qr(A.todense(), pivoting=True)
rows_to_keep = []
for i in range(R.shape[0]):
if np.linalg.norm(R[i, :]) > 1e-10:
rows_to_keep.append(i)
R = R[rows_to_keep, :]
Q = Q[:, rows_to_keep]
# Invert P from col -> var to var -> col.
Pinv = np.zeros(P.size, dtype='int')
for i in range(P.size):
Pinv[P[i]] = i
# Rearrage R.
R = R[:, Pinv]
A = R
b_old = b
b = Q.T.dot(b)
# If b is not in the range of Q,
# the problem is infeasible.
if not np.allclose(b_old, Q.dot(b)):
return s.INFEASIBLE
dims[s.EQ_DIM] = int(b.shape[0])
data["Q"] = intf.dense2cvxopt(Q)
# Remove obviously redundant rows in G's <= constraints.
if dims[s.LEQ_DIM] > 0:
G = G.tocsr()
G_leq = G[:dims[s.LEQ_DIM], :]
h_leq = h[:dims[s.LEQ_DIM]].ravel()
G_other = G[dims[s.LEQ_DIM]:, :]
h_other = h[dims[s.LEQ_DIM]:].ravel()
G_leq, h_leq, P_leq = compress_matrix(G_leq, h_leq)
dims[s.LEQ_DIM] = int(h_leq.shape[0])
data["P_leq"] = intf.sparse2cvxopt(P_leq)
G = sp.vstack([G_leq, G_other])
h = np.hstack([h_leq, h_other])
# Convert A, b, G, h to CVXOPT matrices.
data[s.A] = A
data[s.G] = G
data[s.B] = b
data[s.H] = h
return s.OPTIMAL
