Which speed comparison survives?
Check which classical solver belongs in the benchmark comparison.
The question
A fictional fixed simulation task has a known reference and one required error tolerance. The benchmark records the full time to produce and check the answer.
| Minutes | Output check | |
|---|---|---|
| Quantum workflow | 18 | Pass |
| Classical solver in report | 24 | Pass |
Both rows use the same problem instance, tolerance and timing boundary.
“Is the quantum workflow faster than the fastest available tested classical solver for this task?”
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A strong answer, step by step
Open each step in turn. This is one strong answer, not the only one.
Step 1: What has to match?
What would you do here? Open the move you’d make.
Compare only the number of processing units
Tempting, but it misses something. The question asks about end-to-end time for a checked result.
Assume the two rows are comparable because both say Pass
Tempting, but it misses something. A pass label alone does not identify the task, timing boundary or solver.
Check the solver, problem, tolerance and timing boundary
The strong move. These facts define which measured times can be compared.
See how a strong candidate says it
“I’d check the instance, the output tolerance and what the clock includes. Then I’d identify the classical solver.”
Why it works: A meaningful timing comparison uses the same task and completion rule.
Step 2: What does the report show?
What would you do here? Open the move you’d make.
Six minutes less than the reported solver
The strong move. This comparison uses the evidence that is available.
Twice as fast as the reported solver
Tempting, but it misses something. A twofold ratio would require 36 minutes against 18.
Faster than any classical solver on this task
Tempting, but it misses something. The table only identifies the measured row.
See how a strong candidate says it
“The quantum workflow took 18 minutes. The listed classical solver took 24 minutes. Quantum took six minutes less than that solver in this run.”
Why it works: The ratio applies to the solver in the opening table.
Step 3: Which claim survives the new comparison?
The 24-minute row used an older solver. A current available classical solver completes the same task in 12 minutes with the same tolerance, output check and timing boundary.
What would you do here? Open the move you’d make.
Keep the 4/3 speedup as the best comparison
Tempting, but it misses something. That ratio uses the older solver, which is slower than the new comparator.
Withdraw the speed claim against the fastest tested classical solver
The strong move. The matched classical workflow now takes six fewer minutes.
Withdraw the quantum output check as well
Tempting, but it misses something. The result still met the stated tolerance. The timing comparison changed.
See how a strong candidate says it
“The quantum workflow takes 18/12 = 1.5 times as long as the current solver. I’d withdraw the claim that it is faster than the best tested classical solver.”
Why it works: The output check and timing boundary match. The new solver beats the measured quantum time.
Step 4: What would you report?
What would you do here? Open the move you’d make.
Keep only the old solver because it favors the claim
Tempting, but it misses something. That hides the strongest tested comparator.
Infer that the result applies to larger simulations
Tempting, but it misses something. The packet contains measurements for one problem instance.
Record both classical rows with the shared conditions
The strong move. The record explains why the conclusion changed.
See how a strong candidate says it
“For this test I’d report 18 minutes for the quantum workflow, 24 for the old solver and 12 for the current solver. All three met the stated tolerance.”
Why it works: The named comparisons let another reader see what changed.
The answer, in short
- Decision
- Keep the valid output result and revise the speed comparison.
- Because
- The current matched classical solver runs in 12 minutes and the quantum workflow takes 18.
- What would change it
- Run a new matched comparison for a new task size or tolerance.
Common traps
- Leaving a slower solver as the best comparator
- Extending a one-task timing comparison to other tasks
Check your answer
- Which conditions match?
- Which solver does the opening ratio describe?
- Which is fastest in the updated test?
- What evidence would support a larger claim?
Last reviewed Nov 11, 2026