This research introduces a novel two-parameter family of orthogonal polynomials that emerge as solutions to a doubly confluent Heun-type differential equation. We investigate these polynomials, examining their geometric properties and analyzing the behavior and distribution of their zeros under varying parameter conditions. Leveraging machine learning techniques, we successfully derive symbolic expressions for the corresponding weight functions associated with these orthogonal polynomials. Our numerical results demonstrate the efficacy of this approach, achieving a maximum absolute error of order $ 10^{-4} $ in weight function approximation. Furthermore, we present a comparison between our proposed model and conventional approximation methods, including cubic spline interpolation and Lagrange polynomial interpolation, highlighting the advantages of our methodology.
Citation: Varun Kumar, K. Laxminarayanamma, Abhishek Kumar Singh, Brajesh Shukla, Saiful Rahman Mondal. A machine-learning approach to weight approximation for a new family of orthogonal polynomials[J]. AIMS Mathematics, 2025, 10(8): 18861-18886. doi: 10.3934/math.2025843
This research introduces a novel two-parameter family of orthogonal polynomials that emerge as solutions to a doubly confluent Heun-type differential equation. We investigate these polynomials, examining their geometric properties and analyzing the behavior and distribution of their zeros under varying parameter conditions. Leveraging machine learning techniques, we successfully derive symbolic expressions for the corresponding weight functions associated with these orthogonal polynomials. Our numerical results demonstrate the efficacy of this approach, achieving a maximum absolute error of order $ 10^{-4} $ in weight function approximation. Furthermore, we present a comparison between our proposed model and conventional approximation methods, including cubic spline interpolation and Lagrange polynomial interpolation, highlighting the advantages of our methodology.
| [1] | A. Ronveaux, Heun's differential equations, Oxford: Oxford University Press, 1995. https://doi.org/10.1093/oso/9780198596950.001.0001 |
| [2] |
A. D. Alhaidari, Orthogonal polynomials derived from the tridiagonal representation approach, J. Math. Phys., 59 (2018), 013503. https://doi.org/10.1063/1.5001168 doi: 10.1063/1.5001168
|
| [3] |
E. J. Heller, H. A. Yamani, $J$-Matrix method: Application to S-wave electron-hydrogen scattering, Phys. Rev. A, 9 (1974), 1209–1214. https://doi.org/10.1103/PhysRevA.9.1209 doi: 10.1103/PhysRevA.9.1209
|
| [4] |
A. D. Alhaidari, Series solutions of Laguerre- and Jacobi-type differential equations in terms of orthogonal polynomials and physical applications, J. Math. Phys., 59 (2018), 063508. https://doi.org/10.1063/1.5027158 doi: 10.1063/1.5027158
|
| [5] |
A. D. Alhaidari, H. Bahlouli, Solutions of a Bessel-type differential equation using the tridiagonal representation approach, Rep. Math. Phys., 87 (2021), 313–327. https://doi.org/10.1016/S0034-4877(21)00039-2 doi: 10.1016/S0034-4877(21)00039-2
|
| [6] |
A. D. Alhaidari, Series solutions of Heun-type equation in terms of orthogonal polynomials, J. Math. Phys., 59 (2018), 113507. https://doi.org/10.1063/1.5045341 doi: 10.1063/1.5045341
|
| [7] |
W.-X. Qiu, Z.-Z. Si, D.-S. Mou, C.-Q. Dai, J.-T. Li, W. Liu, Data-driven vector degenerate and nondegenerate solitons of coupled nonlocal nonlinear Schrödinger equation via improved PINN algorithm, Nonlinear Dyn., 113 (2025), 4063–4076. https://doi.org/10.1007/s11071-024-09648-y doi: 10.1007/s11071-024-09648-y
|
| [8] |
Z.-Z. Si, D.-L. Wang, B.-W. Zhu, Z.-T. Ju, X.-P. Wang, W. Liu, et al., Deep learning for dynamic modeling and coded information storage of vector‐soliton pulsations in mode‐locked fiber lasers, Laser Photonics Rev., 18 (2024), 2400097. https://doi.org/10.1002/lpor.202400097 doi: 10.1002/lpor.202400097
|
| [9] |
Y. Wan, Q. Wei, H. Sun, H. Z. B. Wu, Y. M. Zhou, C. W. Bi, et al., Machine learning assisted biomimetic flexible SERS sensor from seashells for pesticide classification and concentration prediction, Chem. Eng. J., 507 (2025), 160813. https://doi.org/10.1016/j.cej.2025.160813 doi: 10.1016/j.cej.2025.160813
|
| [10] |
A. A. Mohammed, A. H. Al-sudani, A. M. Abdul-Hadi, A. Alwhelat, B. M. Mahmmod, S. H. Abdulhussain, et al., Three-dimensional object recognition Using orthogonal polynomials: An embedded kernel approach, Algorithms, 18 (2025), 78. https://doi.org/10.3390/a18020078 doi: 10.3390/a18020078
|
| [11] |
G. R. Vakili-Nezhaad, A. Al Shaaili, R. Yousefzadeh, A. Kazemi, A. Al Ajmi, CO2-Brine interfacial tension correlation based on the classical orthogonal polynomials: monovalent salts with common anion, Chem. Pap., 78 (2024), 3483–3493. https://doi.org/10.1007/s11696-024-03321-9 doi: 10.1007/s11696-024-03321-9
|
| [12] |
Z. Y. Liu, H. F. Wang, H. Zhang, K. J. Bao, X. Qian, S. H. Song, Render unto numerics: Orthogonal polynomial neural operator for PDEs with nonperiodic boundary conditions, SIAM J. Sci. Comput., 46 (2024), 323–348. https://doi.org/10.1137/23M1556320 doi: 10.1137/23M1556320
|
| [13] |
S. R. Mondal, V. Kumar, An orthogonal polynomial solution to the confluent-type Heun's differential equation, Mathematics, 13 (2025), 1233. https://doi.org/10.3390/math13081233 doi: 10.3390/math13081233
|
| [14] |
L. J. El-Jaick, B. D. B. Figueiredo, Solutions for confluent and double-confluent Heun equations, J. Math. Phys., 49 (2008), 083508. https://doi.org/10.1063/1.2970150 doi: 10.1063/1.2970150
|
| [15] |
L. J. El-Jaick, B. D. B. Figueiredo, Confluent Heun equations: convergence of solutions in series of Coulomb wavefunctions, J. Phys. A: Math. Theor., 46 (2013), 085203. https://doi.org/10.1088/1751-8113/46/8/085203 doi: 10.1088/1751-8113/46/8/085203
|
| [16] |
J. Abad, F. J. Gómez, J. Sesma, An algorithm to obtain global solutions of the double confluent Heun equation, Numer. Algor., 49 (2008), 33–51. https://doi.org/10.1007/s11075-008-9197-4 doi: 10.1007/s11075-008-9197-4
|
| [17] |
A. Roseau, On the solutions of double confluent Heun equations, Aequat. Math., 60 (2000), 116–136. https://doi.org/10.1007/s000100050140 doi: 10.1007/s000100050140
|
| [18] | D. Schmidt, G. Wolf, Double confluent Heun equation, In: Heun's differential equations, Oxford: Oxford University Press, 1995,129–188. |
| [19] |
V. M. Buchstaber, S. I. Tertychnyi, Holomorphic solutions of the double confluent Heun equation associated with the RSJ model of the Josephson junction, Theor. Math. Phys., 182 (2015), 329–355. https://doi.org/10.1007/s11232-015-0267-1 doi: 10.1007/s11232-015-0267-1
|
| [20] |
J. D. Yu, C. Z. Li, M. K. Zhu, Y. Chen, Asymptotics for a singularly perturbed GUE, Painlevé Ⅲ, double-confluent Heun equations, and small eigenvalues, J. Math. Phys., 63 (2022), 063504. https://doi.org/10.1063/5.0062949 doi: 10.1063/5.0062949
|
| [21] |
D. Y. Melikdzhanian, A. M. Ishkhanyan, Generalized-hypergeometric solutions of the biconfluent Heun equation, Ramanujan J., 57 (2022), 37–53. https://doi.org/10.1007/s11139-021-00504-w doi: 10.1007/s11139-021-00504-w
|
| [22] |
T. A. Ishkhanyan, A. M. Ishkhanyan, Solutions of the bi-confluent Heun equation in terms of the Hermite functions, Ann. Phys., 383 (2017), 79–91. https://doi.org/10.1016/j.aop.2017.04.015 doi: 10.1016/j.aop.2017.04.015
|
| [23] |
T. A. Ishkhanyan, V. P. Krainov, A. M. Ishkhanyan, Confluent hypergeometric expansions of the confluent Heun function governed by two-term recurrence relations, J. Phys.: Conf. Ser., 1416 (2019), 012014. https://doi.org/10.1088/1742-6596/1416/1/012014 doi: 10.1088/1742-6596/1416/1/012014
|
| [24] |
A. Ishkhanyan, C. Cesarano, Generalized-hypergeometric solutions of the general Fuchsian linear ODE having five regular singularities, Axioms, 8 (2019), 102. https://doi.org/10.3390/axioms8030102 doi: 10.3390/axioms8030102
|
| [25] |
A. M. Ishkhanyan, Appell hypergeometric expansions of the solutions of the general Heun equation, Constr. Approx., 49 (2019), 445–459. https://doi.org/10.1007/s00365-018-9424-8 doi: 10.1007/s00365-018-9424-8
|
| [26] |
G. Lévai, Potentials from the polynomial solutions of the confluent Heun equation, Symmetry, 15 (2023), 461. https://doi.org/10.3390/sym15020461 doi: 10.3390/sym15020461
|
| [27] |
M. Hortaçsu, Heun functions and some of their applications in physics, Adv. High Energy Phys., 2018 (2018), 8621573. https://doi.org/10.1155/2018/8621573 doi: 10.1155/2018/8621573
|
| [28] |
B. D. B. Figueiredo, Schrödinger equation as a confluent Heun equation, Phys. Scr., 99 (2024), 055211. https://doi.org/10.1088/1402-4896/ad3510 doi: 10.1088/1402-4896/ad3510
|
| [29] |
V. M. Buchstaber, S. I. Tertychnyi, Representations of the Klein group determined by quadruples of polynomials associated with the double confluent Heun equation, Math. Notes, 103 (2018), 357–371. https://doi.org/10.1134/S0001434618030033 doi: 10.1134/S0001434618030033
|
| [30] |
A. A. Glutsyuk, On constrictions of phase-lock areas in model of overdamped Josephson effect and transition matrix of the double-confluent Heun equation, J. Dyn. Control Syst., 25 (2019), 323–349. https://doi.org/10.1007/s10883-018-9411-1 doi: 10.1007/s10883-018-9411-1
|
| [31] |
T. Stoyanova, Stokes matrices of a reducible double confluent Heun equation via monodromy matrices of a reducible general Huen equation with symmetric finite singularities, J. Dyn. Control Syst., 28 (2022), 207–245. https://doi.org/10.1007/s10883-021-09571-0 doi: 10.1007/s10883-021-09571-0
|
| [32] |
T. Grava, G. Mazzuca, Generalized Gibbs ensemble of the Ablowitz–Ladik lattice, circular $\beta$-ensemble and double confluent Heun equation, Commun. Math. Phys., 399 (2020), 1689–1729. https://doi.org/10.1007/s00220-023-04642-8 doi: 10.1007/s00220-023-04642-8
|
| [33] |
S. I. Tertichniy, On the Monodromy-Preserving deformation of a double confluent Heun equation, Proc. Steklov Inst. Math., 326 (2024), 303–338. https://doi.org/10.1134/S0081543824040151 doi: 10.1134/S0081543824040151
|
| [34] |
A. Tonda, Review of PySR: high-performance symbolic regression in Python and Julia, Genet. Program. Evolvable Mach., 26 (2025), 7. https://doi.org/10.1007/s10710-024-09503-4 doi: 10.1007/s10710-024-09503-4
|
| [35] |
E. H. Doha, H. M. Ahmed, Recurrences and explicit formulae for the expansion and connection coefficients in series of Bessel polynomials, J. Phys. A: Math. Gen., 37 (2004), 8045. https://doi.org/10.1088/0305-4470/37/33/006 doi: 10.1088/0305-4470/37/33/006
|
| [36] |
W. M. Abd-Elhameed, Novel formulae of certain generalized Jacobi polynomials, Mathematics, 10 (2022), 4237. https://doi.org/10.3390/math10224237 doi: 10.3390/math10224237
|
| [37] |
A. Zhedanov, An explicit example of polynomials orthogonal on the unit circle with a dense point spectrum generated by a geometric distribution, Symmetry Integr. Geom., 16 (2020), 140. https://doi.org/10.3842/SIGMA.2020.140 doi: 10.3842/SIGMA.2020.140
|
| [38] |
W. Van Assche, J. S. Geronimo, Asymptotics for orthogonal polynomials on and off the essential spectrum, J. Approx. Theory, 55 (1988), 220–231. https://doi.org/10.1016/0021-9045(88)90088-3 doi: 10.1016/0021-9045(88)90088-3
|
| [39] |
T. S. Chihara, Orthogonal polynomials with discrete spectra on the real line, J. Approx. Theory, 42 (1984), 97–105. https://doi.org/10.1016/0021-9045(84)90059-5 doi: 10.1016/0021-9045(84)90059-5
|
| [40] |
T. S. Chihara, Orthogonal polynomials whose distribution functions have finite point spectra, SIAM J. Math. Anal., 11 (1980), 358–364. https://doi.org/10.1137/0511033 doi: 10.1137/0511033
|
| [41] | W. B. Langdon, Genetic programming convergence, In: Proceedings of the genetic and evolutionary computation conference companion, New Youk: Association for Computing Machinery, 2022, 27–28. https://doi.org/10.1145/3520304.3534063 |
| [42] |
J. He, L. S. Kang, On the convergence rates of genetic algorithms, Theor. Comput. Sci., 229 (1999), 23–39. https://doi.org/10.1016/S0304-3975(99)00091-2 doi: 10.1016/S0304-3975(99)00091-2
|
| [43] |
F. Hjouj, M. S. Jouini, On orthogonal polynomials and finite moment problem, The Open Chemical Engineering Journal, 16 (2022), e2209260. http://doi.org/10.2174/18741231-v16-e2209260 doi: 10.2174/18741231-v16-e2209260
|
| [44] |
R. Askey, I. J. Schoenberg, A. Sharma, Hausdorff's moment problem and expansions in Legendre polynomials, J. Math. Anal. Appl., 86 (1982), 237–245. https://doi.org/10.1016/0022-247X(82)90267-0 doi: 10.1016/0022-247X(82)90267-0
|
| [45] |
Z. G. Xu, C. X. Liu, T. T. Liang, Tempered fractional neural grey system model with Hermite orthogonal polynomial, ${\overset{\frown} {\rm{Al}}}$ex. Eng. J., 123 (2025), 403–414. https://doi.org/10.1016/j.aej.2025.03.037 doi: 10.1016/j.aej.2025.03.037
|
| [46] |
G. Rudolph, Convergence analysis of canonical genetic algorithms, IEEE T. Neural Networ., 5 (1994), 96–101. https://doi.org/10.1109/72.265964 doi: 10.1109/72.265964
|
| [47] | D. Sudholt, The benefits of population diversity in evolutionary algorithms: A survey of rigorous runtime analyses, In: Theory of evolutionary computation, Cham: Springer, 2019,359–404. https://doi.org/10.1007/978-3-030-29414-4_8 |
| [48] | M. Cranmer, PySR: Tuning and workflow tips, Astroautomata, Available from: https://astroautomata.com/PySR/tuning/. |
| [49] | T. Taheri, A. A. Aghaei, K. Parand, An orthogonal polynomial kernel-based machine learning model for differential-algebraic equations, (2024), arXiv: 2401.14382. https://doi.org/10.48550/arXiv.2401.14382 |
| [50] |
S. Dey, S. Dubey, Orthogonal polynomial-based neural network solution for differential equations with implicit boundary conditions, Int. J. Numer. Method. H., (2025). https://doi.org/10.1108/HFF-11-2024-0901 doi: 10.1108/HFF-11-2024-0901
|