Moog ladder filter
DISADVANTAGES1 · dim 4A baseline wins. At the comparison noise level, the best baseline beats SolvSRK by at least 10 percentage points of survival, or by at least 0.05 balanced score when survival is tied. Use the winning baseline named on the problem page - not SolvSRK. All verdicts →
4-stage tanh transistor ladder filter; resonance near self-oscillation at k≈4
Problem definition
Canonical benchmark implementation
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 rhs(t: float, y: np.ndarray) -> np.ndarray:
V = y.copy()
# Input: 440 Hz tone
u = 0.5 * np.sin(2.0 * np.pi * 440.0 * t)
stages = np.tanh(V)
dV = np.empty(4)
dV[0] = omega_c * (np.tanh(u - k * V[3]) - stages[0])
dV[1] = omega_c * (stages[0] - stages[1])
dV[2] = omega_c * (stages[1] - stages[2])
dV[3] = omega_c * (stages[2] - stages[3])
return dV- Parameters
- k = 3.8
- omega_c = 6283.18530718
- Initial condition
- y(0) = [0, 0, 0, 0]
- Horizon
- t ∈ [0, 0.1]
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: low
Default noise: none
Recommendation snapshot
Clean best: Vern9
Noisy best: SciPy BDF
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: Moog ladder filter (moog-ladder-filter)
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 | Vern9external | 100% | 9.9 | 24,274 | 4.18 s | 0.855 |
| 2 | Vern7external | 100% | 9.1 | 20,372 | 4.14 s | 0.836 |
| 3 | SciPy DOP853SciPy | 100% | 9.0 | 16,178 | 113 ms | 0.834 |
| 4 | SciPy RadauSciPy | 100% | 9.0 | 36,982 | 729 ms | 0.833 |
| 5 | SolvSRK | 100% | 8.9 | 24,631 | 158 ms | 0.832 |
| 6 | Tsit5external | 100% | 7.6 | 19,566 | 2.34 s | 0.801 |
| 7 | SciPy RK45SciPy | 100% | 7.5 | 23,000 | 177 ms | 0.797 |
| 8 | CVODE Adamsexternal | 100% | 6.9 | 3,262 | 33 ms | 0.784 |
| 9 | SciPy BDFSciPy | 100% | 6.2 | 10,438 | 372 ms | 0.766 |
| 10 | SciPy LSODASciPy | 100% | 6.1 | 7,751 | 38 ms | 0.765 |
| 11 | SciPy RK23SciPy | 100% | 6.1 | 57,362 | 544 ms | 0.764 |
| 12 | FBDFexternal | 100% | 6.0 | 15,243 | 4.65 s | 0.762 |
| 13 | CVODE BDFexternal | 100% | 6.0 | 5,592 | 51 ms | 0.761 |
| 14 | TRBDF2external | 100% | 2.3 | 10,022 | 5.05 s | 0.673 |
At Clean, best balanced arm is Vern9 · SolvSRK survival 100%, SCD 8.9.
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_moog_ladder_filter_2026,
title = {Resonix Evidence Portal: Moog ladder filter},
author = {{Resonix Labs (Canada) Inc.}},
year = {2026},
howpublished = {\url{https://resonixusa.com/evidence/problems/moog-ladder-filter}},
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