Overview Evidence tour Methodology Dead zones Problems

HIRES isomerisation

ADVANTAGES3 · dim 8

SolvSRK wins. At the comparison noise level, SolvSRK beats the best baseline by at least 10 percentage points of survival, or by at least 0.05 balanced score when survival is tied. Use SolvSRK for this class of problem. All verdicts →

An eight-species photochemical isomerisation with an extreme stiffness ratio, drawn from the Hairer–Wanner stiff test set. Included to show that SolvSRK matches implicit SciPy on clean precision and then separates under noise.

Chemistry & reaction kinetics

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 _hires_rhs(t, y):
    y1, y2, y3, y4, y5, y6, y7, y8 = y
    return np.array([
        -1.71*y1 + 0.43*y2 + 8.32*y3 + 0.0007,
        1.71*y1 - 8.75*y2,
        -10.03*y3 + 0.43*y4 + 0.035*y5,
        8.32*y2 + 1.71*y3 - 1.12*y4,
        -1.745*y5 + 0.43*y6 + 0.43*y7,
        -280.0*y6*y8 + 0.69*y4 + 1.71*y5 - 0.43*y6 + 0.69*y7,
        280.0*y6*y8 - 1.81*y7,
        -280.0*y6*y8 + 1.81*y7,
    ])

Parameters: No captured parameters; constants are explicit in the RHS excerpt.
Initial condition: y(0) = [1, 0, 0, 0, 0, 0, 0, 0.0057]
Horizon: t ∈ [0, 321.8122]

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: SolvSRK (parity with implicit SciPy)

Noisy best: SolvSRK

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: HIRES isomerisation (hires)

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	SolvSRK	100%	8.0	2,153	9 ms	0.810
2	SciPy DOP853SciPy	100%	7.8	65,210	527 ms	0.805
3	SciPy RadauSciPy	100%	7.4	2,509	50 ms	0.795
4	SciPy RK45SciPy	100%	6.3	71,528	627 ms	0.769
5	Tsit5external	100%	6.0	74,868	7.36 s	0.762
6	SciPy RK23SciPy	100%	5.2	41,978	445 ms	0.744
7	CVODE Adamsexternal	100%	5.0	1,548	34 ms	0.739
8	SciPy LSODASciPy	100%	4.8	1,316	8 ms	0.734
9	SciPy BDFSciPy	100%	4.8	1,087	31 ms	0.733
10	CVODE BDFexternal	100%	4.2	884	27 ms	0.720

At Clean, best balanced arm is SolvSRK.

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_hires_2026,
  title        = {Resonix Evidence Portal: HIRES isomerisation},
  author       = {{Resonix Labs (Canada) Inc.}},
  year         = {2026},
  howpublished = {\url{https://resonixusa.com/evidence/problems/hires}},
  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.}
}

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