Class ILUT

java.lang.Object
no.uib.cipr.matrix.sparse.ILUT
All Implemented Interfaces:
Preconditioner

public class ILUT extends Object implements Preconditioner
ILU preconditioner with fill-in. Uses the dual threshold approach of Saad.
  • Constructor Details

    • ILUT

      public ILUT(FlexCompRowMatrix LU, double tau, int p)
      Sets up the preconditioner for the given matrix
      Parameters:
      LU - Matrix to use internally. For best performance, its non-zero pattern should conform to that of the system matrix
      tau - Drop tolerance
      p - Number of entries to keep on each row in of the factored matrix. This is in addition to the entries of the original matrix
    • ILUT

      public ILUT(FlexCompRowMatrix LU)
      Sets up the preconditioner for the given matrix. Uses a drop-tolerance of 10-6, and keeps 50 entries on each row, including the main diagonal and any previous entries in the matrix structure
      Parameters:
      LU - Matrix to use internally. For best performance, its non-zero pattern should conform to that of the system matrix
  • Method Details

    • apply

      public Vector apply(Vector b, Vector x)
      Description copied from interface: Preconditioner
      Solves the approximate problem with the given right hand side. Result is stored in given solution vector
      Specified by:
      apply in interface Preconditioner
      Parameters:
      b - Right hand side of problem
      x - Result is stored here
      Returns:
      x
    • transApply

      public Vector transApply(Vector b, Vector x)
      Description copied from interface: Preconditioner
      Solves the approximate transpose problem with the given right hand side. Result is stored in given solution vector
      Specified by:
      transApply in interface Preconditioner
      Parameters:
      b - Right hand side of problem
      x - Result is stored here
      Returns:
      x
    • setMatrix

      public void setMatrix(Matrix A)
      Description copied from interface: Preconditioner
      Sets the operator matrix for the preconditioner. This method must be called before a preconditioner is used by an iterative solver
      Specified by:
      setMatrix in interface Preconditioner
      Parameters:
      A - Matrix to setup the preconditioner for. Not modified