def equivalent_resistance(netlist, a, b, sparse=False):
"""Calculate equivalent resistance as seen through nodes a and b.
Works by adding a 1 ampere current generator between a and b, then
solving the circuit. The resistance returned then is
R = [e(a) - e(b)] / 1
Raises
* ValueError: the original netlist has a non-resistor component
* KeyError: either node a or b not found in netlist
"""
if not check_resistive(netlist):
raise ValueError("Network is not resistive")
for node in (a, b):
if node not in netlist.nodenum and node != netlist.ground:
raise KeyError(f"Node `{node}` not found in netlist")
resistive_network = deepcopy(netlist)
resistive_network.process_component(["a1", "A", "1", a, b])
circuit = n.Circuit(resistive_network, sparse=sparse)
solution = circuit.solve()
e = [0, 0]
for i, node in enumerate((a, b)):
if node != "g":
j = solution.nodenum[node]
e[i] = solution.result[j]
return e[0] - e[1]
def assert_print(self, path, expected, mock_stdout):
netlist = n.Netlist(path)
circuit = n.Circuit(netlist)
solution = circuit.solve()
print(solution)
output = mock_stdout.getvalue()
self.assertEqual(output, expected)
def main():
args = parser.parse_args()
try:
netlist = n.Netlist(args.netlist_path)
except FileNotFoundError:
exit(1)
circuit = n.Circuit(netlist, sparse=args.sparse)
try:
solution = circuit.solve()
except n.UnconnectedCircuitError:
exit(1)
print(solution)
def main():
if len(sys.argv) >= 2:
netlist_path = sys.argv[1]
else:
print("Missing argument: netlist file")
exit(1)
if len(sys.argv) == 3:
sparse = sys.argv[2] == "sparse"
else:
sparse = False
try:
netlist = n.Netlist(netlist_path)
except FileNotFoundError:
print("File not found: {}".format(netlist_path))
exit(1)
circuit = n.Circuit(netlist, sparse=sparse)
solution = circuit.solve()
print(solution)