def set_slice_data(linC, linPy):
"""
Loads the slice data, start, stop, and step into our C++ linOp.
The semantics of the slice operator is treated exactly the same as in
Python. Note that the 'None' cases had to be handled at the wrapper level,
since we must load integers into our vector.
"""
for i, sl in enumerate(linPy.data):
slice_vec = cvxcore.IntVector()
for var in [sl.start, sl.stop, sl.step]:
slice_vec.push_back(int(var))
linC.push_back_slice_vec(slice_vec)
def get_problem_matrix(constrs, id_to_col=None, constr_offsets=None):
"""
Builds a sparse representation of the problem data by calling CVXCanon's
C++ build_matrix function.
Parameters
----------
constrs: A list of python linOp trees
id_to_col: A map from variable id to offset withoun our matrix
Returns
----------
V, I, J: numpy arrays encoding a sparse representation of our problem
const_vec: a numpy column vector representing the constant_data in our problem
"""
linOps = [constr.expr for constr in constrs]
lin_vec = cvxcore.LinOpVector()
id_to_col_C = cvxcore.IntIntMap()
if id_to_col is None:
id_to_col = {}
# Loading the variable offsets from our
# Python map into a C++ map
for id, col in list(id_to_col.items()):
id_to_col_C[int(id)] = int(col)
# This array keeps variables data in scope
# after build_lin_op_tree returns
tmp = []
for lin in linOps:
tree = build_lin_op_tree(lin, tmp)
tmp.append(tree)
lin_vec.push_back(tree)
if constr_offsets is None:
problemData = cvxcore.build_matrix(lin_vec, id_to_col_C)
else:
# Load constraint offsets into a C++ vector
constr_offsets_C = cvxcore.IntVector()
for offset in constr_offsets:
constr_offsets_C.push_back(int(offset))
problemData = cvxcore.build_matrix(lin_vec, id_to_col_C,
constr_offsets_C)
# Unpacking
V = problemData.getV(len(problemData.V))
I = problemData.getI(len(problemData.I))
J = problemData.getJ(len(problemData.J))
const_vec = problemData.getConstVec(len(problemData.const_vec))
return V, I, J, const_vec.reshape(-1, 1)
def make_linC_from_linPy(linPy, linPy_to_linC):
"""Construct a C++ LinOp corresponding to LinPy.
Children of linPy are retrieved from linPy_to_linC.
"""
if linPy in linPy_to_linC:
return
typ = get_type(linPy)
shape = cvxcore.IntVector()
lin_args_vec = cvxcore.ConstLinOpVector()
for dim in linPy.shape:
shape.push_back(int(dim))
for argPy in linPy.args:
lin_args_vec.push_back(linPy_to_linC[argPy])
linC = cvxcore.LinOp(typ, shape, lin_args_vec)
linPy_to_linC[linPy] = linC
if linPy.data is not None:
if isinstance(linPy.data, lo.LinOp):
linC_data = linPy_to_linC[linPy.data]
linC.set_linOp_data(linC_data)
linC.set_data_ndim(len(linPy.data.shape))
else:
set_linC_data(linC, linPy)
