Deducting Conserved Quantities for Numerical Schemes using Parametric Groebner Systems

  • Bashayer Majrashi

Student thesis: Master's Thesis


In partial differential equations (PDEs), conserved quantities like mass and momentum are fundamental to understanding the behavior of the described physical systems. The preservation of conserved quantities is essential when using numerical schemes to approximate solutions of corresponding PDEs. If the discrete solutions obtained through these schemes fail to preserve the conserved quantities, they may be physically meaningless and unreliable. Previous approaches focused on checking conservation in PDEs and numerical schemes, but they did not give adequate attention to systematically handling parameters. This is a crucial aspect because many PDEs and numerical schemes have parameters that need to be dealt with systematically. Here, we investigate if the discrete analog of a conserved quantity is preserved under the solution induced by a parametric finite difference method. In this thesis, we modify and enhance a pre-existing algorithm to effectively and reliably deduce conserved quantities in the context of parametric schemes, using the concept of comprehensive Groebner systems. The main contribution of this work is the development of a versatile algorithm capable of handling various parametric explicit and implicit schemes, higher-order derivatives, and multiple spatial dimensions. The algorithm’s effectiveness and efficiency are demonstrated through examples and applications. In particular, we illustrate the process of selecting an appropriate numerical scheme among a family of potential discretization for a given PDE.
Date of AwardMay 2023
Original languageEnglish (US)
Awarding Institution
  • Computer, Electrical and Mathematical Sciences and Engineering
SupervisorDiogo Gomes (Supervisor)


  • Symbolic computations · Finite-difference schemes · Discrete variational derivative · Discrete partial variational derivative · Conserved quantities · Implicit schemes · Explicit schemes · Comprehensive Groebner Systems .

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