def solve_hydraulics(net):
"""
Create and solve the linearized system of equations (based on a jacobian in form of a scipy
sparse matrix and a load vector in form of a numpy array) in order to calculate the hydraulic
magnitudes (pressure and velocity) for the network nodes and branches.
:param net: The pandapipesNet for which to solve the hydraulic matrix
:type net: pandapipesNet
:return:
"""
options = net["_options"]
branch_pit = net["_active_pit"]["branch"]
node_pit = net["_active_pit"]["node"]
branch_lookups = get_lookup(net, "branch", "from_to_active")
for comp in net['component_list']:
if issubclass(comp, BranchComponent):
comp.calculate_derivatives_hydraulic(net, branch_pit, node_pit, branch_lookups, options)
jacobian, epsilon = build_system_matrix(net, branch_pit, node_pit, False)
v_init_old = branch_pit[:, VINIT].copy()
p_init_old = node_pit[:, PINIT].copy()
x = spsolve(jacobian, epsilon)
branch_pit[:, VINIT] += x[len(node_pit):]
node_pit[:, PINIT] += x[:len(node_pit)] * options["alpha"]
return branch_pit[:, VINIT], node_pit[:, PINIT], v_init_old, p_init_old, epsilon
def solve_temperature(net):
"""
This function contains the procedure to build and solve a linearized system of equation based on
an underlying net and the necessary graph data structures. Temperature values are calculated.
Returned are the solution vectors for the new iteration, the original solution vectors and a
vector containing component indices for the system matrix entries
:param net: The pandapipesNet for which to solve the temperature matrix
:type net: pandapipesNet
:return: branch_pit
"""
options = net["_options"]
branch_pit = net["_active_pit"]["branch"]
node_pit = net["_active_pit"]["node"]
branch_lookups = get_lookup(net, "branch", "from_to_active")
# Negative velocity values are turned to positive ones (including exchange of from_node and
# to_node for temperature calculation
branch_pit[:, VINIT_T] = branch_pit[:, VINIT]
branch_pit[:, FROM_NODE_T] = branch_pit[:, FROM_NODE]
branch_pit[:, TO_NODE_T] = branch_pit[:, TO_NODE]
mask = branch_pit[:, VINIT] < 0
branch_pit[mask, VINIT_T] = -branch_pit[mask, VINIT]
branch_pit[mask, FROM_NODE_T] = branch_pit[mask, TO_NODE]
branch_pit[mask, TO_NODE_T] = branch_pit[mask, FROM_NODE]
for comp in net['component_list']:
if issubclass(comp, BranchComponent):
comp.calculate_derivatives_thermal(net, branch_pit, node_pit,
branch_lookups, options)
jacobian, epsilon = build_system_matrix(net, branch_pit, node_pit, True)
t_init_old = node_pit[:, TINIT].copy()
t_out_old = branch_pit[:, T_OUT].copy()
x = spsolve(jacobian, epsilon)
node_pit[:, TINIT] += x[:len(node_pit)] * options["alpha"]
branch_pit[:, T_OUT] += x[len(node_pit):]
return branch_pit[:,
T_OUT], t_out_old, node_pit[:,
TINIT], t_init_old, epsilon