XIANGXIONG
          ZHANG 
        
          
        
        
        
        
        Preprints and publications:
        
        
        
        
        Publications and Accepted Papers in Refereed Journals:
        
          - 54. C. Liu, J. Hu, W. Taitano and X. Zhang, An
            optimization-based positivity-preserving limiter in
            semi-implicit discontinuous Galerkin schemes solving
            Fokker–Planck equations, Computers and Mathematics with
              Applications, Vol. 192, 15 (2025), pp. 54-71. DOI
            PDF  arXiv
 
          
           
          - 53. C. Liu. Z. Sun and X. Zhang, A bound-preserving
            Runge--Kutta discontinuous Galerkin method with compact
            stencils for hyperbolic conservation laws,  Journal of
              Computational Physics, Vol 537 (2025), 114071. arXiv
 
          
           
          - 52. S. Zheng, W. Huang, B. Vandereycken and X. Zhang,
            Riemannian optimization using three different metrics for
            Hermitian PSD fixed-rank constraints, Computational
              Optimization and Applications  (2025)
            Volume 91, pages 1135–1184, DOI.
            PDF. An
            extended version with more details is on arXiv.
 
          
           
        
        
          - 51. W. Hao, S. Lee and X. Zhang, An Efficient Quasi-Newton
            Method with Tensor Product Implementation for Solving
            Quasi-Linear Elliptic Equations and Systems, 
              Journal of Scientific Computing, (2025) 103:89. DOI 
            arXiv
 
          
           
          - 50. Y. Chen, D. Xiu and X. Zhang,  On enforcing
            non-negativity in polynomial approximations in high
            dimensions, SIAM Journal on Scientific Computing, 47,
              no. 2  (2025), A866-A888. DOI PDF arXiv 
 
          
           
          - 49. B. Ren, B.S. Wang, X. Zhang and Z. Gao, Positivity and
            Bound Preserving Well-Balanced Compact Finite Difference
            Scheme for Ripa and Pollutant Transport Systems, Computers
              and Mathematics with Applications, Vol. 176, 15 (2024),
              pp. 545-563. PDF
 
          
           
          - 48. Z. Chen, J. Lu, Y. Lu and X. Zhang, Fully discretized
            Sobolev gradient flow for the Gross-Pitaevskii eigenvalue
            problem, Mathematics of Computation 94 (2025), 2723-2760.
              DOI  arXiv
 
          -  
           
          - 47. C. Liu, G. Buzzard and X. Zhang, An optimization based
            limiter for enforcing positivity in a semi-implicit
            discontinuous Galerkin scheme for compressible Navier–Stokes
            equations,  Journal of Computational Physics,
            519 (2024), pp. 113440.  PDF arXiv 
 
          
           
          - 46. H. Li and X. Zhang, A monotone Q1 finite element
            method for anisotropic elliptic equations, the special issue
            in honor of Prof. Chi-Wang Shu’s 65th birthday in Beijing
              Journal of Pure and Applied Mathematics, Vol. 2, no. 1
            (2025), pp. 183–217. DOI 
            PDF
            arXiv
 
          
           
          - 45. X. Liu, J. Shen and X. Zhang, A simple GPU
            implementation of spectral-element methods for solving 3D
            Poisson type equations on rectangular domains and its
            applications, Communications in Computational Physics,
              Vol. 36, no. 5 (2024), pp. 1157–1185.  DOI  
            PDF  arXiv  Demonstration
              for how to run the code
 
          
           
          - 44. S. Zheng, H. Yang,  and X. Zhang, On the
            convergence of orthogonalization-free conjugate gradient
            method for extreme eigenvalues of Hermitian matrices: a
            Riemannian optimization interpretation. on the special Computational
              Methods and Models in Deep Learning for Inverse Problems,
            Journal of Computational and Applied Mathematics 451
            (2024), pp. 116053. PDF  
 
          
           
          - 43. L. Cross and X. Zhang, On the monotonicity of Q3
            spectral element method for Laplacian, Annals of Applied
              Mathematics 40 (2) (2024), pp. 161–190. PDF doi:
            10.4208/aam.OA-2024-0007
 
          
           
          - 42. C. Liu, B. Riviere, J. Shen and X. Zhang, A simple and
            efficient convex optimization based bound-preserving high
            order accurate limiter for Cahn--Hilliard--Navier--Stokes
            system, SIAM Journal on Scientific Computing, 46,
            no. 3 (2024): A1923-A1948. PDF
            arXiv  
 
          
           
          - 41. M. Dai, M. Hoeller, Q. Peng, and X. Zhang,
            Kolmogorov's dissipation number and determining wavenumber
            for dyadic models. Nonlinearity 37, no. 2 (2024): 025015. DOI
            arXiv
 
          
           
          - 40. Z. Chen, J. Lu, Y. Lu and X. Zhang, On the convergence
            of Sobolev gradient flow for the Gross-Pitaevskii eigenvalue
            problem. SIAM Journal on Numerical Analysis 62
            (2024), pp. 667–691. arXiv
 
          -  
           
          - 39. L. Cross and X. Zhang, On the monotonicity of Q2
            spectral element method for Laplacian on quasi-uniform
            rectangular meshes, Communications in Computational
              Physics, Vol. 35, No. 1, pp. 160-180, 2024. PDF 
            doi:10.4208/cicp.OA-2023-0206
 
          
           
          - 38. C. Liu, Y. Gao and X. Zhang, Structure preserving
            schemes for Fokker-Planck equations of irreversible
            processes,  Journal of Scientific Computing 98(1):4,
              2024. arXiv
 
          
           
          - 37. C. Liu and X. Zhang, A positivity-preserving
            implicit-explicit scheme with high order polynomial basis
            for compressible Navier–Stokes equations,  Journal
              of Computational Physics 493:112496, 2023. PDF
 
          
           
          - 36. M. Dai, B. Vyas and X. Zhang, 1D Model for the 3D
            Magnetohydrodynamics. Journal of Nonlinear Science,
            33, Article number: 87 (2023).  DOI
            PDF
 
          
           
          - 35. X. Liu, J. Shen and X. Zhang, An efficient and robust
            SAV based algorithm  for discrete gradient systems
            arising from optimizations, SIAM Journal on Scientific
              Computing, Vol. 45, No. 5, pp. A2304--A2324, 2023. PDF
 
          
           
          - 34. B. Ren, Z. Gao, Y. Gu, S. Xie, and X. Zhang, A
            positivity-preserving and well-balanced high order compact
            finite difference scheme for shallow water equations, Communications
              in Computational Physics 35 (2024), pp. 524-552. PDF 
 
          
           
          - 33. H. Li and X. Zhang, A high order accurate
            bound-preserving compact finite difference scheme for
            two-dimensional incompressible flow, Communications on
              Applied Mathematics and Computation, Volume 6, pages
            113–141, (2024). Focused Issue in Memory of Prof. Ching-Shan
            Chou. PDF https://doi.org/10.1007/s42967-022-00227-9
 
          
           
          - 32. C. Fan, X. Zhang and J. Qiu, Positivity-preserving
            high order finite difference WENO schemes for the
            compressible Navier-Stokes equations, Journal of
              Computational Physics 467 (2022): 111446. PDF
 
          
           
        
        
          - 31. J. Hu and X. Zhang, Positivity-preserving and
            energy-dissipative finite difference schemes for the
            Fokker-Planck and Keller-Segel equations, IMA Journal of
              Numerical Analysis 43 (2022), pp. 1450–1484. PDF
 
          
           
        
        
          - 30. J. Shen and X. Zhang, Discrete Maximum principle of a
            high order finite difference scheme for a generalized
            Allen-Cahn equation, Communications in Mathematical
              Sciences, Volume 20 (2022) Number 5, pp.1409-1436. PDF
 
          
           
        
        
          - 29. H. Li, D. Appelö and X. Zhang, Accuracy of spectral
            element method for  wave, parabolic and Schrödinger
            equations, SIAM Journal
              on Numerical Analysis 60(1):339–363, 2022. PDF See
            Section 2.8 in
            Hao Li's thesis for
            detailed discussion of Neumann b.c..
 
          
           
          - 28. C. Fan, X. Zhang and J. Qiu, Positivity-preserving
            high order finite volume hybrid Hermite WENO schemes for
            compressible Navier-Stokes equations,  Journal of Computational
              Physics, Volume 445, 2021, 110596. PDF
 
          
           
        
        
          -  27. M. Li, Y. Cheng, J. Shen and X. Zhang,  A
            Bound-Preserving High Order Scheme for Variable Density
            Incompressible Navier-Stokes Equations, Journal of Computational
              Physics 425 (2021): 109906. PDF 
 
          
           
          - 26. H. Li and X. Zhang, On the  monotonicity and
            discrete maximum principle of the finite difference
            implementation of C^0-Q^2 finite element method, Numerische
              Mathematik 145, 437–472 (2020). PDF
 
          
           
          - 25. H. Li and X. Zhang, Superconvergence of high order
            finite difference schemes based on variational formulation
            for elliptic equations, Journal of Scientific Computing
              82, 36 (2020). PDF   
            See Section 2.8 in Hao Li's
              thesis for detailed discussion of Neumann b.c..
             
          
           
          - 24. H. Li and X. Zhang, Superconvergence of C^0-Q^k finite
            element method for elliptic equations with approximated
            coefficients, Journal of
              Scientific Computing 82, 1 (2020). PDF
 
          
           
          - 23. H. Li, S. Xie and X. Zhang, A high order accurate
            bound-preserving compact finite difference scheme for scalar
            convection diffusion equations, SIAM Journal on Numerical Analysis, 2018,
            56(6), 3308-3345. PDF
 
          
           
          - 22. S. Srinivasan, J. Poggie and X. Zhang, A
            positivity-preserving high order discontinuous Galerkin
            scheme for convection-diffusion equations,  Journal of Computational
              Physics, Vol 366, 2018, Pages 120-143.  PDF 
 
          
           
          - 21. J. Hu, R. Shu and X. Zhang, Asymptotic-preserving
            and positivity-preserving implicit-explicit schemes for the
            stiff BGK equation, SIAM
              Journal on Numerical Analysis, 2018, 56(2),
            942–973.  PDF 
 
          
           
          - 20. J. Hu and X. Zhang, On a class of
            implicit-explicit Runge Kutta schemes for stiff kinetic
            equations preserving the Navier-Stokes limit,  Journal
              of Scientific Computing, (2017) 73: 797-818.  PDF
 
          
           
          - 19. W. Huang, K. Gallivan and X. Zhang, Solving PhaseLift
            by low-rank Riemannian optimization methods for complex
            semidefinite constraints. SIAM Journal on Scientific
              Computing, 39-5 (2017), . CODE.
            PDF
 
        
        
          
           
          - 18. X. Zhang, On positivity-preserving high order
            discontinuous Galerkin schemes for compressible
            Navier-Stokes equations, Journal of Computational
              Physics,  328 (2017):
            301–343. DOI. PDF
 
          
           
          - 17. X. Zhang, A curved boundary treatment for
            discontinuous Galerkin schemes solving time dependent
            problems, Journal of Computational Physics,
            308 (2016): 153-170. DOI.
              PDF.
 
        
        
          
           
          - 16. X. Cai, X. Zhang and J. Qiu, Positivity-preserving
            high order finite volume HWENO schemes for compressible
            Euler equations, Journal of Scientific Computing,
            (2016) 68: 464. DOI.   PDF.
 
          
           
          - 15. X. Zhang and S. Tan, A simple and accurate
            discontinuous Galerkin scheme for modeling scalar-wave
            propagation in media with curved interfaces, GEOPHYSICS
            Mar 2015, Vol. 80, No. 2, pp. T83-T89. DOI. 
              PDF.
 
          
           
          - 14. L. Demanet and X. Zhang, Eventual linear convergence
            of the Douglas Rachford iteration for basis pursuit, Mathematics
              of Computation 85 (2016), 209-238. DOI.
               PDF. 
 
          -  
           
          - 13. Y. Xing and X. Zhang, Positivity-preserving
            well-balanced discontinuous Galerkin methods for the shallow
            water equations on unstructured triangular meshes, Journal
              of Scientific Computing, v57 (2013), pp. 19-41. DOI.
               PDF.
 
          
           
          - 12. Y. Zhang, X. Zhang and C.-W. Shu,
            Maximum-principle-satisfying second order discontinuous
            Galerkin schemes for convection-diffusion equations on
            triangular meshes, Journal of Computational Physics,
            v234 (2013), pp. 295-316. DOI.
               PDF. 
 
          
           
          - 11. X. Zhang, Y.-Y. Liu and C.-W. Shu,
            Maximum-principle-satisfying high order finite volume WENO
            schemes for convection-diffusion equations, SIAM
              Journal on Scientific Computing, v34 (2012),
            pp.A627-A658. DOI.
               PDF.
 
          
           
          - 10. X. Zhang and C.-W. Shu, Positivity-preserving high
            order finite difference WENO schemes for compressible Euler
            equations, Journal of Computational Physics,
            v231 (2012), pp.2245-2258. DOI.
               PDF. 
 
          
           
          - 9. X. Zhang and C.-W. Shu, A minimum entropy principle of
            high order schemes for gas dynamics equations, Numerische
              Mathematik, (2012) 121:545-563. DOI.
               PDF.
 
          
           
          - 8. C. Wang, X. Zhang, C.-W. Shu and J. Ning, Robust high
            order discontinuous Galerkin schemes for two-dimensional
            gaseous detonations, Journal of Computational Physics,
            v231 (2012), pp.653-665. DOI.
               PDF.
 
          
           
          - 7. X. Zhang and C.-W. Shu, Maximum-principle-satisfying
            and positivity-preserving high order schemes for
            conservation laws: Survey and new developments, Proceedings
              of the Royal Society A: Mathematical, Physical and
              Engineering Sciences, v467 (2011), pp.2752-2776. DOI.
              PDF.  See
            Appendix C in this
              paper for a correction to the proof of Lemma 1. 
 
          
           
          - 6. X. Zhang and C.-W. Shu, Positivity-preserving high
            order discontinuous Galerkin schemes for compressible Euler
            equations with source terms, Journal of Computational
              Physics, v230 (2011), pp.1238-1248. DOI.
               PDF.
 
        
        
          
           
          - 5. X. Zhang, Y. Xia and C.-W. Shu,
            Maximum-principle-satisfying and positivity-preserving high
            order discontinuous Galerkin schemes for conservation laws
            on triangular meshes, Journal of Scientific Computing,
            v50 (2012), pp.29-62. DOI.
              PDF.
 
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          - 4. Y. Xing, X. Zhang and C.-W. Shu, Positivity preserving
            high order well balanced discontinuous Galerkin methods for
            the shallow water equations, Advances in Water
              Resources, v33 (2010), pp.1476-1493. DOI.
              PDF.
 
          
           
        
        
          - 3. X. Zhang and C.-W. Shu, On positivity preserving high
            order discontinuous Galerkin schemes for compressible Euler
            equations on rectangular meshes, Journal of
              Computational Physics, v229 (2010), pp.8918-8934. DOI.
               PDF.
 
          
           
          - 2. X. Zhang and C.-W. Shu, On maximum-principle-satisfying
            high order schemes for scalar conservation laws, Journal
              of Computational Physics, v229 (2010), pp.
            3091-3120. DOI.
              PDF.
             See Appendix C in this paper for a
            correction to the proof of Lemma 2.4.
 
        
        
          
           
          - 1. X. Zhang and C.-W. Shu, A genuinely high order total
            variation diminishing scheme for one-dimensional scalar
            conservation laws, SIAM Journal on Numerical Analysis,
            Volume 48, Issue 2 (2010), pp. 772-795. DOI.  
            PDF.
 
           
           
        
        
        
        
          - 5. X. Zhang, Recent Progress on Qk Spectral Element
            Method: Accuracy, Monotonicity and Applications, to appear
            in: Sehun Chun, Jae-Hun Jung, Eun-Jae Park, and Jie
              Shen, editors, Spectral and High-Order Methods for
            Partial Differential Equations ICOSAHOM 2023, volume 142 of
            Lecture Notes in Computational Science and Engineering.
            Springer, Cham, 2025. PDF 
 
          
           
          - 4. Z. Xu and X. Zhang, Bound-preserving high order
            schemes, Volume 18, Handbook of Numerical Methods for
            Hyperbolic Problems: Applied and Modern Issues, R. Abgrall
            and C.-W. Shu, Editors, North-Holland, Elsevier, Amsterdam,
            2017, pp. 81-102.   PDF
 
        
        
        
          
            
              -  3. Wen Huang, Kyle A. Gallivan, Xiangxiong Zhang,
                Solving PhaseLift by Low-rank Riemannian Optimization
                Methods, The International Conference on Computational
                Science 2016, ICCS 2016, 6-8 June 2016, San Diego,
                California, USA. Procedia Computer Science, Volume 80,
                2016, Pages 1125-1134, ISSN 1877-0509, DOI
 
              
               
              - 2. X. Zhang and S. Tan, A simple and accurate
                discontinuous Galerkin scheme for modeling scalar-wave
                propagation in media with curved interfaces, in Proc.
                SEG annual meeting, Denver, October 2014. DOI
 
              
               
              - 1. M. Leinonen, R. J. Hewett, X. Zhang, L. Ying, L.
                Demanet, High-dimensional wave atoms and compression of
                seismic datasets, in Proc. SEG annual meeting, Houston,
                September 2013. DOI.
                PDF. 
 
              
               
            
             
            
              
              
              
              - 1. T. Yu, S. Zheng, J. Lu, G. Menon and X. Zhang,
                Riemannian Langevin Monte Carlo schemes for sampling PSD
                matrices with fixed rank. PDF  arXiv
 
              
               
            
            - 2. A. Anshika, J. Li, D. Ghosh and X. Zhang, A
              Three-Operator Splitting Scheme Derived from Three-Block
              ADMM, submitted to MOPTA 24 special issue of Optimization
              and Engineering. PDF    
              arXiv  
              code
 
          
          -  
 
          - 3. K. Wu, X. Zhang and C.-W. Shu, High Order Numerical
            Methods Preserving Invariant Domain for Hyperbolic and
            Related Systems. 
           
          - 4. E. Gil Torres, M. Jacobs, and X. Zhang, Asymptotic
            Linear Convergence of ADMM for Isotropic TV Norm Compressed
            Sensing, PDF
              arXiv
 
          
           
          - 5. C. Liu, D. Milesis, C.-W. Shu, and X. Zhang, Efficient
            optimization-based invariant-domain-preserving limiters in
            solving gas dynamics equations, PDF arXiv