Neutron point kinetics (6 delayed groups)
PARITYS3 · dim 7No clear winner. The survival gap is under 10 percentage points and the balanced-score gap is under 0.05, so neither SolvSRK nor the best baseline clears the win threshold. Either works - choose on cost, licensing, or integration effort. All verdicts →
Seven-state neutron point kinetics with six delayed-neutron groups and a step reactivity insertion (Ganapol benchmark). A parity case: SolvSRK tracks SciPy Radau closely on both clean precision and noise survival.
Problem definition
Ganapol (2024); Yamoah, Akaho, Nyarko (2013)
Canonical RHS excerpt from the registered callable used for this benchmark cell. Expand it to verify the state equations; it is not a standalone runnable fixture.
Show canonical RHS excerpt
def _point_kinetics_rhs(t, y):
"""dn/dt = (rho-beta)/Lambda * n + sum(lambda_i * C_i); dC_i/dt = beta_i/Lambda * n - lambda_i * C_i."""
n = max(y[0], 0.0) # neutron density must stay non-negative
C = y[1:7]
dn = _RHO_MINUS_BETA_OVER_LAMBDA * n + np.dot(_LAMBDA_I, C)
dC = _BETA_I_OVER_LAMBDA * n - _LAMBDA_I * C
dy = np.empty(7)
dy[0] = dn
dy[1:7] = dC
return dy- Parameters
- _BETA_I_OVER_LAMBDA = [0.532, 2.982, 2.632, 5.698, 1.792, 0.364]
- _LAMBDA_I = [0.0127, 0.0317, 0.115, 0.311, 1.4, 3.87]
- _RHO_MINUS_BETA_OVER_LAMBDA = -7.5
- Initial condition
- y(0) = [1, 41.8897637795, 94.0694006309, 22.8869565217, 18.3215434084, 1.28, 0.0940568475452]
- Horizon
- t ∈ [0, 10]
Canonical RHS excerpt captured from the same registered callable used for the published benchmark. Frozen closure values are summarized below; helper imports and solver settings are intentionally omitted.
Fingerprint
Spread: extreme
Default noise: clean
Recommendation snapshot
Clean best: parity (SolvSRK ≈ SciPy Radau)
Noisy best: parity
Coverage
14 solver arms · clean + 5 noise levels
Ranked on survival, precision, and speed
Versions & freeze
Methodology →- Freeze
- 2026-08-13
- libsolvsrk
- 2.3.0
- SciPy
- 1.14
- SUNDIALS
- CVODE (bundled backend)
20 seeds/cell default · 14 arms · TRL 4–5 · simulation-lab validated · this page: Neutron point kinetics (6 delayed groups) (point_kinetics_6g)
Governed SolvTune benchmark freeze; per-arm medians only. RHS definitions and raw trial rows are not published.
Self-reported by Resonix Labs · not independently verified
Results matrix
Pick an objective and a noise level to rank all arms on survival, median SCD, median nfev, and median wall time. Medians across seeds.
Objective
Best overall trade-off of survival, precision, and speed.
Noise level
| # | Solver | Survival | SCD | nfev | Wall | Score |
|---|---|---|---|---|---|---|
| 1 | SciPy RadauSciPy | 100% | 11.4 | 946 | 19 ms | 0.891 |
| 2 | SolvSRK | 100% | 11.2 | 820 | 24 ms | 0.885 |
| 3 | SciPy DOP853SciPy | 100% | 10.2 | 290 | 2 ms | 0.863 |
| 4 | Tsit5external | 100% | 9.7 | 330 | 734 ms | 0.850 |
| 5 | SciPy RK45SciPy | 100% | 9.1 | 362 | 3 ms | 0.835 |
| 6 | CVODE Adamsexternal | 100% | 8.2 | 206 | 8 ms | 0.815 |
| 7 | SciPy LSODASciPy | 100% | 8.2 | 302 | 2 ms | 0.813 |
| 8 | SciPy BDFSciPy | 100% | 8.1 | 332 | 12 ms | 0.811 |
| 9 | CVODE BDFexternal | 100% | 8.0 | 225 | 9 ms | 0.809 |
| 10 | SciPy RK23SciPy | 100% | 7.8 | 1,235 | 12 ms | 0.806 |
At Clean, best balanced arm is SciPy Radau · SolvSRK survival 100%, SCD 11.2.
Values are medians across seeds, measured by Resonix Labs on Resonix hardware and not independently verified; nfev and wall are on reference lab hardware (indicative). Under injected noise only SolvSRK and the SciPy arms are run. How we measure accuracy → · Verification status →
Cite this page
Replace the access date. Pin the freeze ID and library versions when comparing against a later export. Cite it as what it is - a self-reported vendor benchmark, not an independently verified result. The note field says so; please keep it.
@misc{resonix_evidence_point_kinetics_6g_2026,
title = {Resonix Evidence Portal: Neutron point kinetics (6 delayed groups)},
author = {{Resonix Labs (Canada) Inc.}},
year = {2026},
howpublished = {\url{https://resonixusa.com/evidence/problems/point_kinetics_6g}},
note = {Self-reported vendor benchmark; internally generated by Resonix Labs and not independently verified. Accessed YYYY-MM-DD. Freeze 2026-08-13; libsolvsrk 2.3.0; SciPy 1.14.}
}Related
TRL 4–5 · simulation-lab validated · 398 problems · 14 solver arms · clean + 5 noise levels
Freeze: 2026-08-13 · scipy 1.14 · libsolvsrk 2.3.0 · Methodology
Self-reported by Resonix Labs · not independently verified · Verification status