REVIEW 4 major objections 6 minor 37 references
Systems of ODEs Parameters Estimation by Using Stochastic Newton-Raphson and Gradient Descent Methods
T0 review · 4 major / 6 minor · reviewed 2026-08-10 · deepseek-v4-flash
Pith's one-line read This paper claims that ODE parameters can be estimated directly by fitting finite-difference derivatives to the system's right-hand side with Newton-Raphson or gradient descent updates, and that these direct methods beat nonlinear least…
desk verdict Derivative matching with a non-uniform grid twist, but the 'outperforms NLS' claim rests on a constrained baseline that is clearly stuck at bounds. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The object that carries the argument is the residual vector $E(t,x,\bar a)=f(t,x,\bar a)-x'(t)$, with the derivative $x'(t)$ obtained from a finite-difference formula (first-order from two consecutive time points, or second-order from three points). Linearizing $f$ by Taylor expansion converts the residual into a linear system in $\Delta a$, enabling the Newton-Raphson update $a_{i+1}=a_i-\gamma\,\nabla_a F\,E$ and the gradient descent update $a_{i+1}=a_i-\eta\,\nabla_a G\,G$. The machinery includes the Jacobian $\nabla_a F$ (static for systems linear in parameters, updated each iteration otherwise), the explicit step-size rule for GD, and the random subsampling that defines the stochastic variants SNR and SGD.
What would settle it
Generate Lorenz-system data with known parameters and additive noise, compute $x'(t)$ using the paper's equation (12), and check whether the NR/GD estimates converge to the true parameters as the number of data points $N$ grows. If the estimates remain biased even for large $N$, or if the residual objective's global minimum is not at the true parameter vector, the central claim fails.
Extended reading notes
Core claim
On the paper's own terms, the central discovery is that parameter estimation for systems of ODEs can be posed as a direct residual-minimization problem in parameter space using discrete derivatives and Taylor expansion, solvable by Newton-Raphson (NR) and gradient descent (GD). The residual is $E(t,x,\bar a)=f(t,x,\bar a)-x'(t)$, where $x'(t)$ is approximated by the first- or second-order finite differences in equations (6) and (12); expanding $f$ in a Taylor series in $a$ gives the linear system $E=-\nabla_a F\,\Delta a$, which NR solves with the pseudo-inverse step $\gamma=(\nabla_a F^\top\nabla_a F)^{-1}$. GD instead uses the explicit step size $\eta=\delta^\top G/\delta^\top\delta$ with $\delta=\nabla_a G\,\nabla_a G^\top G$. Stochastic versions randomly select $r$ of the $n$ ODE equations each iteration to cut cost. Across three numerical examples, the estimated parameters from both methods are closer to the generating parameters than those from constrained NLS, with error metrics closer to zero and $R^2$ closer to one.
Load-bearing premise
The finite-difference derivative computed from noisy data is close enough to the true derivative that the residual $f(t,x,a)-x'(t)$ has its minimum at the true parameters, an assumption that is especially fragile for chaotic systems where state errors amplify.
Editorial extensions
If this is right
- Newton-Raphson on the direct derivative residual can converge in one or two iterations for systems linear in parameters, giving very fast estimates from clean or mildly noisy data.
- Gradient descent with the explicit step size provides a robust fallback for chaotic systems, where Newton-Raphson may jump to a poor local solution.
- Stochastic subsampling of the ODE equations makes the method scalable to large data sets by reducing the per-iteration Jacobian and residual size.
- If the accuracy comparison to NLS holds, the direct method is a practical choice for real data fitting when the ODE lacks an explicit solution and numerical integration is expensive.
- The finite-difference formulas accommodate irregular sampling intervals, so the method applies directly to experimental data with varying time steps.
Reading between the lines
- Beyond the paper: the direct derivative-matching objective is a variant of gradient matching, and its bias under measurement noise is well known; a natural extension would be to derive the asymptotic bias of the NR/GD estimates and to add smoothing or regularization to the derivative estimate.
- Beyond the paper: the authors compare against NLS with the same initial guesses, but do not report the basin of attraction for GD on the Lorenz system; measuring how often random restarts converge to the true parameters would sharpen the robustness claim.
- Beyond the paper: the stochastic variants randomly subsample equations, not data points; an alternative extension is to subsample time points or use mini-batches of the residual, which could further reduce cost on very long time series.
- Beyond the paper: the finite-difference derivative amplifies noise in chaotic systems, so a testable extension is to repeat the Lorenz experiment at several noise levels and check whether the parameter estimates remain closer to truth than NLS when the derivative is noisier.
Signed reviews
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes a direct derivative-matching approach for estimating parameters in systems of ODEs. The ODE residual is formed by comparing a finite-difference approximation of the state derivative (Eqs. (6) and (12)) with the model right-hand side f(t,x,a), and the parameters are updated by Newton-Raphson (Eq. (16)) or gradient descent (Eq. (30)) iteratively, with stochastic variants defined in Algorithms 2 and 4. The method is demonstrated on population dynamics, Lorenz, and activator-inhibitor examples, and the abstract claims that the proposed methods outperform nonlinear least squares (NLS). Convergence theorems are stated in Section 2.1 (Theorem 1) and Section 2.2 (Theorem 2).
Significance. If the central claim were established, the derivative-matching formulation would offer a computationally cheap alternative to NLS for ODE parameter estimation. However, the manuscript has load-bearing deficiencies: the convergence proof contains an impossible inequality, the numerical comparison to NLS is not apples-to-apples because the NLS baseline is constrained while the proposed methods are unconstrained, the stochastic variants are never numerically evaluated, and the treatment of noisy finite-difference derivatives is not analyzed. The paper does not currently provide a credible demonstration of its headline claim of improved accuracy over NLS.
major comments (4)
- [Section 2.2, Eq. (39)] Equation (39) states "0 ≥ δ⊤δ = G(t, x, ai)⊤ Π² G(t, x, ai) + O(∥μi∥³)". Since δ⊤δ is a sum of squares, it is always nonnegative, so the inequality cannot be correct as written; the only consistent statement would be 0 ≤ δ⊤δ. This sign error invalidates the derivation of the linear convergence bound in Eq. (41), which relies on the incorrect direction of the inequality. This is a load-bearing error in the GD convergence analysis.
- [Section 3.1.4, 3.2.4, and 3.3.4] The claim that the proposed methods outperform NLS is not supported by the reported experiments because the comparison is not fair: the NLS baseline is solved as a constrained optimization with bounds (Eqs. (52), (57), (62)), while the proposed methods are unconstrained. The reported NLS solutions sit at or near the active bounds (a3=2 in Eq. (58) and a3≈0.052 in Eq. (63)), suggesting that the NLS solver is finding constrained local optima rather than the true unconstrained optimum. No multi-start, solver tolerance, or convergence diagnostics are reported for NLS. Therefore Tables 3, 7, and 10 do not establish the paper's central claim of outperforming NLS.
- [Section 3 (numerical implementation)] The stochastic versions SNR and SGD are defined in Algorithms 2 and 4, but the numerical examples only apply the deterministic NR and GD methods (Algorithms 1 and 3). No results are reported for the stochastic variants, despite the title, abstract, and conclusion emphasizing their contribution for large-scale systems. The statement in the introduction to Section 3 that the application of Algorithms 2 and 4 is presented in Python is not followed by any stochastic numerical experiment. Consequently, the claims about scalability and reduced computational cost for big data are unsupported.
- [Section 2, Eqs. (6) and (12)] The objective E in Eq. (14) is built from finite-difference derivatives of noisy data. The paper does not analyze how noise propagates through these derivative approximations or how that affects the estimated parameters. For the chaotic Lorenz system in Section 3.2, small state errors amplify exponentially, and the reported results are based on single realizations, so the accuracy claims are not demonstrable. Since the entire method rests on the reliability of these derivative approximations, this missing analysis is a load-bearing gap.
minor comments (6)
- [Title and throughout] The title contains a typo: "ODE S" should read "ODEs".
- [Section 3.1, Eq. (45)] The second equation writes "dx2/dx" instead of "dx2/dt".
- [Section 2.1, Eq. (16)] The step length γ is defined as the inverse of the Gram matrix of the Jacobian, which is appropriate only when the Jacobian has full column rank; the paper does not state this assumption.
- [Section 2.2, Eq. (31)] The citation "Barzilai and Bowein, 1988" should be "Barzilai and Borwein, 1988".
- [Section 3.2.3, text near Table 4] The sentence "The optimal estimated parameters ¯a int Table 4" contains a typo: "int" should be "in".
- [Section 3.2.3, Table 4] The layout of the NR row in Table 4 is confusing because the convergent parameter vector is placed in the last cell, making it difficult to associate it with the corresponding initial guess.
Circularity Check
No circularity: the derivative-residual parameter estimation is self-contained; reported estimates are simulation fits, not predictions forced by construction.
full rationale
The paper's derivation chain builds an objective E(t,x,a) = f(t,x,a) - discrete derivative (Eq. (14), with discrete derivative from Eq. (6)/(12)) and then solves for parameters via Newton-Raphson (Eq. (16)) or gradient descent (Eq. (30)). This is a standard gradient-matching formulation, and the parameter updates are derived from Taylor expansions of the residual, not from the target parameters themselves. The numerical experiments generate data from known parameters, add noise, and fit parameters, reporting the fitted values as estimates; no held-out prediction is claimed, and no fitted parameter is renamed as a prediction. The comparison to NLS is a benchmark comparison, not part of the derivation, and any weakness in that comparison (constrained NLS, possible local minima) is a correctness concern, not circularity. The paper contains no self-citations that carry a load-bearing role, and no uniqueness theorem or prior-work ansatz is imported to force the chosen formulation. The central method's behavior therefore rests on its own stated equations and data, so the derivation is not equivalent to its inputs by construction.
Assumptions & free parameters
free parameters (4)
- Taylor expansion order n =
not specified
- GD step size eta (Barzilai-Borwein style delta) =
computed by Eq. (31)
- Stopping tolerance epsilon =
not specified
- Stochastic mini-batch size r for SNR/SGD =
not specified
assumptions (4)
- standard math Taylor's theorem applies and the remainder is negligible on the observed grid
- domain assumption The finite-difference derivative of noisy data approximates the true derivative well
- ad hoc to paper The ODE model f is twice continuously differentiable with non-vanishing Jacobian at the optimum
- domain assumption Noise is additive, Gaussian, and not filtered
Cite this review
Pith. "Pith review of Systems of ODEs Parameters Estimation by Using Stochastic Newton-Raphson and Gradient Descent Methods." pith.science (2026). https://pith.science/paper/K7DNDZOD
@misc{pith2026250112856,
author = {Pith},
title = {Pith review of: Systems of ODEs Parameters Estimation by Using Stochastic Newton-Raphson and Gradient Descent Methods},
year = {2026},
howpublished = {\url{https://pith.science/paper/K7DNDZOD}},
note = {Machine review of arXiv:2501.12856}
}
read the original abstract
Ordinary differential equations (ODEs) are widely used to describe the time evolution of natural phenomena across various scientific fields. Estimating the parameters of these systems from data is a challenging task, particularly when dealing with nonlinear and high-dimensional models. In this paper, we propose novel methodologies for parameter estimation in systems of ODEs by using the Newton-Raphson (NR) method and Gradient Descent (GD) method. By leveraging the discrete derivative and Taylor expansion, the problem is formulated in a way that enables the application of both methods, allowing for flexible, efficient solutions. Additionally, we extend these approaches to stochastic versions - Stochastic Newton-Raphson (SNR) and Stochastic Gradient Descent (SGD) - to handle large-scale systems with reduced computational cost. The proposed methods are evaluated by using numerical examples, including both linear and nonlinear parameter models, and compare the results to the well-known Nonlinear Least Squares (NLS) method. While NR converges rapidly to the optimal solution, GD demonstrates robustness in handling chaotic systems, though it may occasionally lead to suboptimal results. Overall, the proposed methods provide improved accuracy in parameter estimation for ODE systems, outperforming NLS in terms of error metrics such as bias, mean absolute error (MAE), mean absolute percentage error (MAPE), root mean square error (RMSE), and coefficient of determination R2. These methods offer a valuable tool for fitting ODE models, particularly in scenarios involving big data and complex dynamics.
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Works this paper leans on
-
[1]
[1] #1 [1] #1 urlstyle [1] doi: #1 doi: rm
-
[2]
M. Hwang and J. H. Seinfeld. A new algorithm for the estimation of parameters in ordinary differential equations. AIChE Journal, 18 0 (1): 0 90--93, 1972
work page 1972
-
[3]
George R. Gavalas. A new method of parameter estimation in linear systems. AIChE Journal, 19 0 (2): 0 214--222, 1973
work page 1973
-
[4]
J. L. Howland and R. Vaillancourt. A generalized curve-fitting procedure. Journal of the society for industrial and applied mathematics, 9 0 (2): 0 165--168, 1961
work page 1961
-
[5]
A preprocessing method for parameter estimation in ordinary differential equations
Oliver Strebel. A preprocessing method for parameter estimation in ordinary differential equations. Chaos Soliton and Fractals, 57: 0 93--104, 2023
work page 2023
-
[6]
Ozgur Aydogmus and Ali Hakan Tor. A modified multiple shooting algorithm for parameter estimation in odes using adjoint sensitivity analysis. Applied Mathematics and Computation, 390: 0 125644, 2021
work page 2021
-
[7]
A Bayesian Collocation Integral Method for Parameter Estimation in Ordinary Differential Equations
Mingwei Xu, Samuel WK Wong, and Peijun Sang. A bayesian collocation integral method for parameter estimation in ordinary differential equations. arXiv preprint arXiv:2304.02127, 2023
work page Pith review arXiv 2023
-
[8]
Zhengfeng Li, Michael R. Osborne, and Tania Prvan. Parameter estimation of ordinary differential equations. IMA Journal of Numerical Analysis, 25 0 (2): 0 264--285, 2005
work page 2005
Show all 37 references
-
[9]
J. M. Varah. A spline least squares method for numerical parameter estimation in differential equations. SIAM Journal on Scientific and Statistical Computing, 3 0 (1): 0 10.1137/0903003, 1982
1982 doi
-
[10]
Nicolas J. B. Brunel, Quentin Clairon, and Florence D'Alch\' e -Buc. Parametric estimation of ordinary differential equations with orthogonality conditions. Journal of the American Statical Association, 109 0 (505): 0 173 -- 185, 2014
2014
-
[11]
Huang, and Hulin Wu
Jiguo Cao, Jianhua Z. Huang, and Hulin Wu. Penalized nonlinear least squares estimation of time-varying parameters in ordinary differential equations. Journal of computational and graphical statistics, 21 0 (1): 0 42--56, 2012
2012
-
[12]
Vincent J. Aidala. Parameter estimation via the kalman filter. IEEE Transactions on Automatic Control, 22: 0 471--472, 1977. ISSN 0018-9286,1558-2523. doi:10.1109/tac.1977.1101518. URL http://doi.org/10.1109/tac.1977.1101518
1977
-
[13]
Parameter estimation for signals described by differential equations
Mamadou Mboup. Parameter estimation for signals described by differential equations. Applicable Analysis, 88 0 (1): 0 29--52, 2008
2008
-
[14]
Peifer and J
M. Peifer and J. Timmer. Parameter estimation in ordinary differential equations for biological processes using the method of multiple shooting. IET Systems Biology, 1 0 (2): 0 78--88, 2007
2007
-
[15]
J. O. Ramsay, G Hooker, D Campbell, and J Cao. Parameter estimation for differential equations: a generalized smoothing approach. Journal of the Royal Statistical Society Series B: Statistical Methodology, 69 0 (5): 0 741--796, 2007
2007
-
[16]
Baake, M
E. Baake, M. Baake, H. G. Bock, and K. M. Briggs. Fitting ordinary differential equations to chaotic data. Physical Review A, 45: 0 5524--5529, Apr 1992. doi:10.1103/PhysRevA.45.5524. URL https://link.aps.org/doi/10.1103/PhysRevA.45.5524
1992 doi
-
[17]
J. Timmer. Parameter estimation in nonlinear stochastic differential equations. Chaos, Solitons & Fractals, 11 0 (15): 0 2571--2578, 2000
2000
-
[18]
Mbalawata, Simo S\" a rkk\" a , and Heikki Haario
Isambi S. Mbalawata, Simo S\" a rkk\" a , and Heikki Haario. Parameter estimation in stocastic differential equations with markov chain monte carlo and nonlinear kalman filter. Computational statistics, 28: 0 1195 -- 1223, 2013
2013
-
[19]
Numerical method for parameter inference of systems of nonlinear ordinary differential equations with partial observations
Yu Chen, Jin Cheng, Huaxiong Huang Arvind Gupta, and Shixin Xu. Numerical method for parameter inference of systems of nonlinear ordinary differential equations with partial observations. Royal Society Open Science, 8: 0 210171, 2021
2021
-
[20]
Parameter estimation for rough differential equations
Anastasia Papavasiliou and Christophe Ladroue. Parameter estimation for rough differential equations. The Annals of Statistics, 39 0 (4): 0 2047 -- 2073, 2011
2011
-
[21]
Parameter estimation of nonlinear stochastic differential equations: Simulated maximum likelihood versus extended kalman filter and it\^ o -taylor expansion
Hermann Singer. Parameter estimation of nonlinear stochastic differential equations: Simulated maximum likelihood versus extended kalman filter and it\^ o -taylor expansion. Journal of computational and graphical statistics, 11 0 (4): 0 972 -- 995, 2002
2002
-
[22]
Jan Nygaard Nielsen, Henrik Madsen, and Peter C. Young. Parameter estimation in stochastic differential equations: an overview. Annual Reviews in Control, 24: 0 83--94, 2000
2000
-
[23]
Xiaolei Xun, Jiguo Cao, Bani Mallick, Arnab Maity, and Raymond J. Carroll. Parameter estimation of partial differential equations models. Journal of the American statitical association, 108 0 (503): 0 1009--1020, 2013
2013
-
[24]
Siamak Mehrkanoon, Saeid Mehrkanoon, and Johan A. K. Suykens. Parameter estimation of delay differential equations: an integration-free ls-svm approach. Communications in nonlinear science and numerical simulation, 19 0 (4): 0 830--841, 2014
2014
-
[25]
Parameter estimation and adaptive control of euler-lagrange systems using the power balance equation parameterisation
Jose Guadalupe Romero, Romeo Ortega, and Alexey Bobtsov. Parameter estimation and adaptive control of euler-lagrange systems using the power balance equation parameterisation. International journal of control, 96 0 (2): 0 475--487, 2021
2021
-
[26]
An artificial neural network approximation based decomposition approach for parameter estimation of system of ordinary differential equations
Vivek Dua. An artificial neural network approximation based decomposition approach for parameter estimation of system of ordinary differential equations. Computer & Chemical Engineering, 35 0 (3): 0 545--553, 2011
2011
-
[27]
A simultaneous approach for parameter estimation of a system ofordinary differential equations, using artificial neural networkapproximation
Vivek Dua and Pinky Dua. A simultaneous approach for parameter estimation of a system ofordinary differential equations, using artificial neural networkapproximation. Industrial and Engineering Chemistry Research, 51: 0 1809--1814, 2012
2012
-
[28]
Two-stage approach to parameter estimation of differential equations using neural odes
William Bradley and Fani Boukouvala. Two-stage approach to parameter estimation of differential equations using neural odes. Industrial and Engineering Chemistry Research, 60: 0 16330--16344, 2021
2021
-
[29]
Parameter estimation of partial differential equations using artificial neural network
Elnaz Jamili and Vivek Dua. Parameter estimation of partial differential equations using artificial neural network. Computers & Chemical Engineering, 147: 0 107221, 2021
2021
-
[30]
Parameter estimation in ordinary differential equations modeling via particle swarm optimization
Devin Akman, Olcay Akman, and Elsa Schaefer. Parameter estimation in ordinary differential equations modeling via particle swarm optimization. Journal of applied mathematics, 2018 0 (Article ID 9160793), 2018
2018
-
[31]
J. W. Neuberger. Steepest descent and differential equations. Journal of the Mathematical Society of Japan, 37 0 (2): 0 187--195, 1985
1985
-
[32]
Improving the efficiency of gradient descent algorithms applied to optimization problems with dynamical constraints
Ion Matei, Maksym Zhenirovskyy, Johan de Kleer, and John Maxwell. Improving the efficiency of gradient descent algorithms applied to optimization problems with dynamical constraints. arXiv, 2208.12834v1, 2022
2022 arXiv
-
[33]
Parameter identification of arx models based on modified momentum gradient descent algorithm
Quan Tu, Yingjao Rong, and Jing Chen. Parameter identification of arx models based on modified momentum gradient descent algorithm. Complexity, 2020: 0 Article ID 9537075, 2020
2020
-
[34]
J Barzilai and J. M. Bowein. Two-point step size gradient methods. IMA Journal of Numerical Analysis, 8 0 (1): 0 141--148, 1988
1988
-
[35]
Y. H. Dai. Alternate step gradient method. Optimization, 52 0 (4-5): 0 395--415, 2003
2003
-
[36]
Raydan and B
M. Raydan and B. F Svaiter. Relaxed steepest descent and cauchy-barzilai-borwein method. Computational Optimization and Applications, 21 0 (2): 0 155--167, 2002
2002
-
[37]
A gradient descent method for solving a system of nonlinear equations
Wenrui Hao. A gradient descent method for solving a system of nonlinear equations. Applied Mathematics Letters, 112: 0 106739, 2021
2021
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