# PLaSK User Manual

#### Page Contents

- DynamicCyl

# DynamicCyl

<thermal solver="DynamicCyl">

  Corresponding Python class: `thermal.dynamic.DynamicCyl`.

  Two-dimensional dynamic thermal solver in cylindrical geometry, based on finite-element method.

  Attributes:

    - name (`required`) – Solver name.

  Contents:
    <geometry>

      Geometry for use by this solver.

      Attributes:

        - ref (`required`) – Name of a Cylindrical geometry defined in the `<geometry>` section.

    <mesh>

      Rectangular2D mesh used by this solver.

      Attributes:

        - ref (`required`) – Name of a Rectangular2D mesh defined in the `<grids>` section.

    <mesh>

      Rectangular2D mesh used by this solver.

      Attributes:

        - ref (`required`) – Name of a Rectangular2D mesh defined in the `<grids>` section. (mesh)

        - empty-elements – Should empty regions (e.g. air) be included into electrical computations? (`default`, `include`, or `exclude`, default is `default`)

    <temperature>

      Temperature boundary conditions. See subsection Boundary conditions.

    <loop>

      Configuration of the time-evolution loop.

      Attributes:

        - inittemp – Initial temperature used for the first computation. (float (K), default 300 K)

        - timestep – Single-iteration time step. (float (ns), default 0.1 ns)

        - rebuildfreq – Number of iterations until the whole matrix is rebuilt. The larger this number is, the more efficient computations are, however it may be less accurate is material parameters strongly depend on temperature. If this parameter is set to zero, matrix is never rebuilt. (int, default 0)

        - logfreq – Number of iterations until the computations progress is reported. (int, default 500)

    <matrix>

      Matrix solver configuration.

      Attributes:

        - algorithm – Algorithm used for solving set of linear positive-definite equations. (`cholesky`, `gauss`, or `iterative`, default is `cholesky`)

        - methodparam – Mid-step parameter for implicit finite-difference time discretization. Defaults to ½, which results in the Crank-Nicholson method. 0 makes the method explicit, while 1 results in backward Euler method. (float, default 0.5)

        - lumping – This attribute determines whether the mass matrix is lumped or non-lumped (consistent). (bool, default is `yes`)

      <iterative>

        Parameters for iterative matrix solver. PLaSK uses NSPCG package for performing iterations. Please refer to its documentation for explanation of most of the settings.

        Attributes:

          - maxit – Maximum number of iterations. (int, default 1000)

          - maxerr – Maximum iteration error. (float, default 1e-6)

          - noconv – Desired behavior if the iterative solver does not converge. (`error`, `warning`, or `continue`, default is `warning`)

          - accelerator – Accelerator used for iterative matrix solver. (`cg`, `si`, `sor`, `srcg`, `srsi`, `basic`, `me`, `cgnr`, `lsqr`, `odir`, `omin`, `ores`, `iom`, `gmres`, `usymlq`, `usymqr`, `landir`, `lanmin`, `lanres`, `cgcr`, or `bcgs`, default is `cg`)

          - preconditioner – Preconditioner used for iterative matrix solver. (`rich`, `jac`, `ljac`, `ljacx`, `sor`, `ssor`, `ic`, `mic`, `lsp`, `neu`, `lsor`, `lssor`, `llsp`, `lneu`, `bic`, `bicx`, `mbic`, or `mbicx`, default is `ic`)

          - nfact – This number initializes the frequency of partial factorizations. It specifies the number of linear system evaluations between factorizations. The default value is 1, which means that a factorization is performed at every iteration. (int, default 10)

          - ndeg – Degree of the polynomial to be used for the polynomial preconditioners. (int, default 1)

          - lvfill – Level of fill-in for incomplete Cholesky preconditioners. Increasing this value will result in more accurate factorizations at the expense of increased memory usage and factorization time. (int, default 0)

          - ltrunc – Truncation bandwidth to be used when approximating the inverses of matrices with dense banded matrices. An increase in this value means a more accurate factorization at the expense of increased storage. (int, default 0)

          - omega – Relaxation parameter. (float, default 1.0)

          - nsave – The number of old vectors to be saved for the truncated acceleration methods. (int, default 5)

          - nrestart – The number of iterations between restarts for the restarted acceleration methods. (int, default 100000)

        Preconditioner choices:
        `rich` | Richardson’s method
        `jac` | Jacobi method
        `ljac` | Line Jacobi method
        `ljacx` | Line Jacobi method (approx. inverse)
        `sor` | Successive Overrelaxation
        `ssor` | Symmetric SOR (can be used only with SOR accelerator)
        `ic` | Incomplete Cholesky (default)
        `mic` | Modified Incomplete Cholesky
        `lsp` | Least Squares Polynomial
        `neu` | Neumann Polynomial
        `lsor` | Line SOR
        `lssor` | Line SSOR
        `llsp` | Line Least Squares Polynomial
        `lneu` | Line Neumann Polynomial
        `bic` | Block Incomplete Cholesky (ver. 1)
        `bicx` | Block Incomplete Cholesky (ver. 2)
        `mbic` | Modified Block Incomplete Cholesky (ver. 1)
        `mbicx` | Modified Block Incomplete Cholesky (ver. 2)

        Accelerator choices:
        `cg` | Conjugate Gradient acceleration (default)
        `si` | Chebyshev acceleration or Semi-Iteration
        `sor` | Successive Overrelaxation (can use only SOR preconditioner)
        `srcg` | Symmetric Successive Overrelaxation Conjugate Gradient Algorithm (can use only SSOR preconditioner)
        `srsi` | Symmetric Successive Overrelaxation Semi-Iteration Algorithm (can use only SSOR preconditioner)
        `basic` | Basic Iterative Method
        `me` | Minimal Error Algorithm
        `cgnr` | Conjugate Gradient applied to the Normal Equations
        `lsqr` | Least Squares Algorithm
        `odir` | ORTHODIR, a truncated/restarted method useful for nonsymmetric systems of equations
        `omin` | ORTHOMIN, a common truncated/restarted method used for nonsymmetric systems
        `ores` | ORTHORES, another truncated/restarted method for nonsymmetric systems
        `iom` | Incomplete Orthogonalization Method
        `gmres` | Generalized Minimal Residual Method
        `usymlq` | Unsymmetric LQ
        `usymqr` | Unsymmetric QR
        `landir` | Lanczos/ORTHODIR
        `lanmin` | Lanczos/ORTHOMIN or Biconjugate Gradient Method
        `lanres` | Lanczos/ORTHORES or “two-sided” Lanczos Method
        `cgcr` | Constrained Generalized Conjugate Residual Method
        `bcgs` | Biconjugate Gradient Squared Method