CPU vs GPU comparison
Aggregated across 24 runs in results/.
Per-arm mean ± standard error.
Arms are keyed by backend and ansatz mode where a run declares one.
A legacy_full and a matched
LiH run share a backend and a Hamiltonian but execute different circuits
(12 qubits / 92 parameters versus 10 / 24), so they are never averaged
together and CPU/GPU ratios are only computed within a single mode.
H2
0.96x cpu_over_gpu_fp64_wall_time
1.30x cpu_over_gpu_fp32_wall_time
| backend | n | wall time (s) | time/eval (ms) | evaluations | |err vs ref| (Ha) |
|---|---|---|---|---|---|
| gpu_fp64 | 3 | 17.653 ± 1.076 | 221.58 ± 0.36 | 79.7 ± 4.8 | 1.75e-07 |
| gpu_fp32 | 3 | 12.976 ± 0.390 | 222.43 ± 0.54 | 58.3 ± 1.7 | 2.83e-06 |
| cpu | 3 | 16.872 ± 0.833 | 229.01 ± 1.71 | 73.7 ± 3.5 | 1.75e-07 |
LIH
1.08x matched/cpu_over_gpu_fp64_wall_time
| backend | n | wall time (s) | time/eval (ms) | evaluations | |err vs ref| (Ha) |
|---|---|---|---|---|---|
| cpu · matched | 5 | 773.379 ± 30.075 | 732.91 ± 0.12 | 1055.2 ± 40.9 | 2.99e-08 |
| gpu_fp64 · matched | 5 | 719.399 ± 5.503 | 698.44 ± 0.46 | 1030.0 ± 7.8 | 2.99e-08 |
| gpu_fp64 · legacy_full | 5 | 1068.843 ± 3.470 | 712.56 ± 2.31 | 1500.0 ± 0.0 | 3.12e-02 |