human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "gpu accelerated spectral finite elements on all hex meshes"
  Abstract: This paper presents a spectral element finite element scheme that efficiently solves elliptic problems on unstructured hexahedral meshes. The discrete equations are solved using a matrix-free preconditioned conjugate gradient algorithm. An additive Schwartz two-scale preconditioner is employed that allows h-independence convergence. An extensible multi-threading programming API is used as a common kernel language that allows runtime selection of different computing devices (GPU and CPU) and different threading interfaces (CUDA, OpenCL and OpenMP). Performance tests demonstrate that problems with over 50 million degrees of freedom can be solved in a few seconds on an off-the-shelf GPU.

Connected through hyperedge HE-1 (induced by source paper "finding hexahedrizations for small quadrangulations of the sphere"):
  with members:
    - "a 36 element solution to schneiders pyramid hex meshing problem and a parity changing template for hex mesh revision"
    - "a 44 element mesh of schneiders pyramid bounding the difficulty of hex meshing problems"
    - "identifying combinations of tetrahedra into hexahedra a vertex based strategy"
    - "flipping cubical meshes"
    - "subgraph isomorphism in planar graphs and related problems"
    - "linear complexity hexahedral mesh generation"

Connected through hyperedge HE-2 (induced by source paper "locality optimized unstructured mesh algorithms on gpus"):
  with members:
    - "accelerating unstructured finite volume computations on field programmable gate arrays"

Connected through hyperedge HE-3 (induced by source paper "there are 174 subdivisions of the hexahedron into tetrahedra"):
  with members:
    - "practical graph isomorphism ii"

Connected through hyperedge HE-4 (induced by source paper "fast matrix free evaluation of discontinuous galerkin finite element operators"):
  with members:
    - "exa dune flexible pde solvers numerical methods and applications"
    - "a study of vectorization for matrix free finite element methods"
    - "efficient explicit time stepping of high order discontinuous galerkin schemes for waves"
    - "firedrake automating the finite element method by composing abstractions"
    - "an algorithm for the optimization of finite element integration loops"
    - "factorizing the factorization a spectral element solver for elliptic equations with linear operation count"
    - "loo py transformation based code generation for gpus and cpus"
    - "achieving high performance with unified residual evaluation"

Connected through hyperedge HE-5 (induced by source paper "acceleration of tensor product operations for high order finite element methods"):
  with members:
    - "a unified optimization approach for sparse tensor operations on gpus"
    - "tensor contractions with extended blas kernels on cpu and gpu"

Connected through hyperedge HE-6 (induced by source paper "robust and efficient validation of the linear hexahedral element"):
  with members:
    - "identifying combinations of tetrahedra into hexahedra a vertex based strategy"
    - "a bernstein bezier sufficient condition for invertibility of polynomial mapping functions"

Connected through hyperedge HE-7 (induced by source paper "array program transformation with loo py by example high order finite elements"):
  with members:
    - "cross loop optimization of arithmetic intensity for finite element local assembly"
    - "loo py from fortran to performance via transformation and substitution rules"
    - "occa a unified approach to multi threading languages"
    - "loo py transformation based code generation for gpus and cpus"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.CE(Computational Engineering, Finance, and Science)