ResourceExceeded
ResourceExceeded (Python: menos.exceptions.ResourceExceededError) means no plan fits the constraints. It is a refusal, not a crash: MENOS will not run something it knows it cannot run within budget.
When it is raised
| Cause | Stage |
|---|---|
| Every candidate needs more memory than the budget | Plan time |
| Every candidate is estimated to exceed the time budget | Plan time |
| A run overran its time budget and no other plan fits | Run time |
| A device allocation would exceed GPU memory | Plan time (the region falls back to CPU first) |
It is raised before any allocation for plan-time causes, so a refusal never leaves a half-built state.
Reading the message
The message lists every candidate's reason, separated by semicolons, so you can see exactly what blocked each one:
text
plan_job: no feasible candidate -- direct dense simulation requires 17592186044416 bytes,
budget is 7752519680 bytes; the stabilizer engine does not track global phase -- only the
dense engine can produce a statevector; …A run-time refusal names the observation:
text
menos::run: observed runtime of 0.25 s exceeded the job's time budget of 1e-06 s after 3 safe
boundaries on engine=stabilizer backend=cpu, and no different plan meets that budget -- …Handling it
python
from menos import Circuit, Opcode, RunOptions, run
from menos.exceptions import ResourceExceededError
circuit = Circuit(40, 0)
circuit.append(Opcode.H, [0])
for q in range(39):
circuit.append(Opcode.CX, [q, q + 1])
options = RunOptions()
options.want_statevector = True
try:
run(circuit, options)
except ResourceExceededError as error:
print("cannot run:", str(error)[:80])
else:
raise AssertionError("a 40-qubit dense statevector cannot fit in memory")What to try
| If the cause was | Try |
|---|---|
| memory | Ask for less: counts or an expectation value instead of a statevector; a circuit that splits into parts; a smaller circuit; a larger memory budget if the machine has the RAM |
| time, at plan time | A larger budget, or an output that is cheaper to compute |
| time, at run time | A larger budget; the abandoned plan's engine was slower than predicted |
Hierarchy
ResourceExceededError derives from MenosError. Catch MenosError to handle any MENOS failure. See Exceptions.