slepc4py.SLEPc.PEP — slepc4py 3.24.2 documentation

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# slepc4py.SLEPc.PEP

class slepc4py.SLEPc.PEP

  Bases: `Object`

  Polynomial Eigenvalue Problem Solver.

  The Polynomial Eigenvalue Problem (`PEP`) solver is the object provided by slepc4py for specifying a polynomial eigenvalue problem. Apart from the specific solvers for this type of problems, there is an `EPS`-based solver, i.e., it uses a solver from `EPS` to solve a generalized eigenproblem obtained after linearization.

  Enumerations

  `Basis` | PEP basis type for the representation of the polynomial.
  `CISSExtraction` | PEP CISS extraction technique.
  `Conv` | PEP convergence test.
  `ConvergedReason` | PEP convergence reasons.
  `ErrorType` | PEP error type to assess accuracy of computed solutions.
  `Extract` | PEP extraction strategy used.
  `JDProjection` | PEP type of projection to be used in the Jacobi-Davidson solver.
  `ProblemType` | PEP problem type.
  `Refine` | PEP refinement strategy.
  `RefineScheme` | PEP scheme for solving linear systems during iterative refinement.
  `Scale` | PEP scaling strategy.
  `Stop` | PEP stopping test.
  `Type` | PEP type.
  `Which` | PEP desired part of spectrum.

  Methods Summary

  `appendOptionsPrefix`([prefix]) | Append to the prefix used for searching for all PEP options in the database.
  `cancelMonitor`() | Clear all monitors for a `PEP` object.
  `computeError`(i[, etype]) | Compute the error associated with the i-th computed eigenpair.
  `create`([comm]) | Create the PEP object.
  `destroy`() | Destroy the PEP object.
  `errorView`([etype, viewer]) | Display the errors associated with the computed solution.
  `getBV`() | Get the basis vectors object associated to the eigensolver.
  `getBasis`() | Get the type of polynomial basis used.
  `getCISSExtraction`() | Get the extraction technique used in the CISS solver.
  `getCISSKSPs`() | Get the array of linear solver objects associated with the CISS solver.
  `getCISSRefinement`() | Get the values of various refinement parameters in the CISS solver.
  `getCISSSizes`() | Get the values of various size parameters in the CISS solver.
  `getCISSThreshold`() | Get the values of various threshold parameters in the CISS solver.
  `getConverged`() | Get the number of converged eigenpairs.
  `getConvergedReason`() | Get the reason why the `solve()` iteration was stopped.
  `getConvergenceTest`() | Get the method used to compute the error estimate used in the convergence test.
  `getDS`() | Get the direct solver associated to the eigensolver.
  `getDimensions`() | Get the number of eigenvalues to compute and the dimension of the subspace.
  `getEigenpair`(i[, Vr, Vi]) | Get the i-th solution of the eigenproblem as computed by `solve()`.
  `getEigenvalueComparison`() | Get the eigenvalue comparison function.
  `getErrorEstimate`(i) | Get the error estimate associated to the i-th computed eigenpair.
  `getExtract`() | Get the extraction technique used by the `PEP` object.
  `getInterval`() | Get the computational interval for spectrum slicing.
  `getIterationNumber`() | Get the current iteration number.
  `getJDFix`() | Get threshold for changing the target in the correction equation.
  `getJDMinimalityIndex`() | Get the maximum allowed value of the minimality index.
  `getJDProjection`() | Get the type of projection to be used in the Jacobi-Davidson solver.
  `getJDRestart`() | Get the restart parameter used in the Jacobi-Davidson method.
  `getJDReusePreconditioner`() | Get the flag for reusing the preconditioner.
  `getLinearEPS`() | Get the eigensolver object associated to the polynomial eigenvalue solver.
  `getLinearExplicitMatrix`() | Get if the matrices for the linearization are built explicitly.
  `getLinearLinearization`() | Get the coeffs.
  `getMonitor`() | Get the list of monitor functions.
  `getOperators`() | Get the matrices associated with the eigenvalue problem.
  `getOptionsPrefix`() | Get the prefix used for searching for all PEP options in the database.
  `getProblemType`() | Get the problem type from the PEP object.
  `getQArnoldiLocking`() | Get the locking flag used in the Q-Arnoldi method.
  `getQArnoldiRestart`() | Get the restart parameter used in the Q-Arnoldi method.
  `getRG`() | Get the region object associated to the eigensolver.
  `getRefine`() | Get the refinement strategy used by the PEP object.
  `getRefineKSP`() | Get the `KSP` object used by the eigensolver in the refinement phase.
  `getST`() | Get the spectral transformation object associated to the eigensolver.
  `getSTOARCheckEigenvalueType`() | Get the flag for the eigenvalue type check in spectrum slicing.
  `getSTOARDetectZeros`() | Get the flag that enforces zero detection in spectrum slicing.
  `getSTOARDimensions`() | Get the dimensions used for each subsolve step.
  `getSTOARInertias`() | Get the values of the shifts and their corresponding inertias.
  `getSTOARLinearization`() | Get the coefficients that define the linearization of a quadratic eigenproblem.
  `getSTOARLocking`() | Get the locking flag used in the STOAR method.
  `getScale`([Dl, Dr]) | Get the strategy used for scaling the polynomial eigenproblem.
  `getStoppingTest`() | Get the stopping test function.
  `getTOARLocking`() | Get the locking flag used in the TOAR method.
  `getTOARRestart`() | Get the restart parameter used in the TOAR method.
  `getTarget`() | Get the value of the target.
  `getTolerances`() | Get the tolerance and maximum iteration count.
  `getTrackAll`() | Get the flag indicating whether all residual norms must be computed.
  `getType`() | Get the PEP type of this object.
  `getWhichEigenpairs`() | Get which portion of the spectrum is to be sought.
  `reset`() | Reset the PEP object.
  `setBV`(bv) | Set a basis vectors object associated to the eigensolver.
  `setBasis`(basis) | Set the type of polynomial basis used.
  `setCISSExtraction`(extraction) | Set the extraction technique used in the CISS solver.
  `setCISSRefinement`([inner, blsize]) | Set the values of various refinement parameters in the CISS solver.
  `setCISSSizes`([ip, bs, ms, npart, bsmax, ...]) | Set the values of various size parameters in the CISS solver.
  `setCISSThreshold`([delta, spur]) | Set the values of various threshold parameters in the CISS solver.
  `setConvergenceTest`(conv) | Set how to compute the error estimate used in the convergence test.
  `setDS`(ds) | Set a direct solver object associated to the eigensolver.
  `setDimensions`([nev, ncv, mpd]) | Set the number of eigenvalues to compute and the dimension of the subspace.
  `setEigenvalueComparison`(comparison[, args, ...]) | Set an eigenvalue comparison function.
  `setExtract`(extract) | Set the extraction strategy to be used.
  `setFromOptions`() | Set PEP options from the options database.
  `setInitialSpace`(space) | Set the initial space from which the eigensolver starts to iterate.
  `setInterval`(inta, intb) | Set the computational interval for spectrum slicing.
  `setJDFix`(fix) | Set the threshold for changing the target in the correction equation.
  `setJDMinimalityIndex`(flag) | Set the maximum allowed value for the minimality index.
  `setJDProjection`(proj) | Set the type of projection to be used in the Jacobi-Davidson solver.
  `setJDRestart`(keep) | Set the restart parameter for the Jacobi-Davidson method.
  `setJDReusePreconditioner`(flag) | Set a flag indicating whether the preconditioner must be reused or not.
  `setLinearEPS`(eps) | Set an eigensolver object associated to the polynomial eigenvalue solver.
  `setLinearExplicitMatrix`(flag) | Set flag to explicitly build the matrices for the linearization.
  `setLinearLinearization`([alpha, beta]) | Set the coefficients that define the linearization of a quadratic eigenproblem.
  `setMonitor`(monitor[, args, kargs]) | Append a monitor function to the list of monitors.
  `setOperators`(operators) | Set the matrices associated with the eigenvalue problem.
  `setOptionsPrefix`([prefix]) | Set the prefix used for searching for all PEP options in the database.
  `setProblemType`(problem_type) | Set the type of the polynomial eigenvalue problem.
  `setQArnoldiLocking`(lock) | Toggle between locking and non-locking variants of the Q-Arnoldi method.
  `setQArnoldiRestart`(keep) | Set the restart parameter for the Q-Arnoldi method.
  `setRG`(rg) | Set a region object associated to the eigensolver.
  `setRefine`(ref[, npart, tol, its, scheme]) | Set the refinement strategy used by the PEP object.
  `setST`(st) | Set a spectral transformation object associated to the eigensolver.
  `setSTOARCheckEigenvalueType`(flag) | Set flag to check if all eigenvalues have the same definite type.
  `setSTOARDetectZeros`(detect) | Set flag to enforce detection of zeros during the factorizations.
  `setSTOARDimensions`([nev, ncv, mpd]) | Set the dimensions used for each subsolve step.
  `setSTOARLinearization`([alpha, beta]) | Set the coefficients that define the linearization of a quadratic eigenproblem.
  `setSTOARLocking`(lock) | Toggle between locking and non-locking variants of the STOAR method.
  `setScale`(scale[, alpha, Dl, Dr, its, lbda]) | Set the scaling strategy to be used.
  `setStoppingTest`(stopping[, args, kargs]) | Set a function to decide when to stop the outer iteration of the eigensolver.
  `setTOARLocking`(lock) | Toggle between locking and non-locking variants of the TOAR method.
  `setTOARRestart`(keep) | Set the restart parameter for the TOAR method.
  `setTarget`(target) | Set the value of the target.
  `setTolerances`([tol, max_it]) | Set the tolerance and maximum iteration count.
  `setTrackAll`(trackall) | Set flag to compute the residual of all approximate eigenpairs.
  `setType`(pep_type) | Set the particular solver to be used in the PEP object.
  `setUp`() | Set up all the internal data structures.
  `setWhichEigenpairs`(which) | Set which portion of the spectrum is to be sought.
  `solve`() | Solve the polynomial eigenproblem.
  `valuesView`([viewer]) | Display the computed eigenvalues in a viewer.
  `vectorsView`([viewer]) | Output computed eigenvectors to a viewer.
  `view`([viewer]) | Print the PEP data structure.

  Attributes Summary

  `bv` | The basis vectors (`BV`) object associated.
  `ds` | The direct solver (`DS`) object associated.
  `extract` | The type of extraction technique to be employed.
  `max_it` | The maximum iteration count.
  `problem_type` | The type of the eigenvalue problem.
  `rg` | The region (`RG`) object associated.
  `st` | The spectral transformation (`ST`) object associated.
  `target` | The value of the target.
  `tol` | The tolerance.
  `track_all` | Compute the residual norm of all approximate eigenpairs.
  `which` | The portion of the spectrum to be sought.

  Methods Documentation

  appendOptionsPrefix(prefix=None)

    Append to the prefix used for searching for all PEP options in the database.

    Logically collective.

    Parameters:

      prefix (str | None) – The prefix string to prepend to all PEP option requests.

    Return type:

      None

    See also

    `setOptionsPrefix`, `getOptionsPrefix`, `PEPAppendOptionsPrefix`

    Source code at slepc4py/SLEPc/PEP.pyx:467

  cancelMonitor()

    Clear all monitors for a `PEP` object.

    Logically collective.

    See also

    `PEPMonitorCancel`

    Source code at slepc4py/SLEPc/PEP.pyx:1589

    Return type:

      None

  computeError(i, etype=None)

    Compute the error associated with the i-th computed eigenpair.

    Collective.

    Compute the error (based on the residual norm) associated with the i-th computed eigenpair.

    Parameters:

      - i (int) – Index of the solution to be considered.

      - etype (ErrorType | None) – The error type to compute.

    Returns:

      The error bound, computed in various ways from the residual norm \(\|P(\lambda)x\|_2\) where \(\lambda\) is the eigenvalue and \(x\) is the eigenvector.

    Return type:

      `float`

    Notes

    The index `i` should be a value between `0` and `nconv-1` (see `getConverged()`).

    See also

    `getErrorEstimate`, `PEPComputeError`

    Source code at slepc4py/SLEPc/PEP.pyx:1785

  create(comm=None)

    Create the PEP object.

    Collective.

    Parameters:

      comm (Comm | None) – MPI communicator. If not provided, it defaults to all processes.

    Return type:

      Self

    See also

    `PEPCreate`

    Source code at slepc4py/SLEPc/PEP.pyx:350

  destroy()

    Destroy the PEP object.

    Collective.

    See also

    `PEPDestroy`

    Source code at slepc4py/SLEPc/PEP.pyx:324

    Return type:

      Self

  errorView(etype=None, viewer=None)

    Display the errors associated with the computed solution.

    Collective.

    Display the errors and the eigenvalues.

    Parameters:

      - etype (ErrorType | None) – The error type to compute.

      - viewer (petsc4py.PETSc.Viewer | None) – Visualization context; if not provided, the standard output is used.

    Return type:

      None

    Notes

    By default, this function checks the error of all eigenpairs and prints the eigenvalues if all of them are below the requested tolerance. If the viewer has format `ASCII_INFO_DETAIL` then a table with eigenvalues and corresponding errors is printed.

    See also

    `solve`, `valuesView`, `vectorsView`, `PEPErrorView`

    Source code at slepc4py/SLEPc/PEP.pyx:1823

  getBV()

    Get the basis vectors object associated to the eigensolver.

    Not collective.

    Returns:

      The basis vectors context.

    Return type:

      `BV`

    See also

    `setBV`, `PEPGetBV`

    Source code at slepc4py/SLEPc/PEP.pyx:1250

  getBasis()

    Get the type of polynomial basis used.

    Not collective.

    Returns:

      The basis that was previously set.

    Return type:

      `Basis`

    See also

    `setBasis`, `PEPGetBasis`

    Source code at slepc4py/SLEPc/PEP.pyx:505

  getCISSExtraction()

    Get the extraction technique used in the CISS solver.

    Not collective.

    Returns:

      The extraction technique.

    Return type:

      `CISSExtraction`

    See also

    `setCISSExtraction`, `PEPCISSGetExtraction`

    Source code at slepc4py/SLEPc/PEP.pyx:2729

  getCISSKSPs()

    Get the array of linear solver objects associated with the CISS solver.

    Collective.

    Returns:

      The linear solver objects.

    Return type:

      `list` of `petsc4py.PETSc.KSP`

    Notes

    The number of `petsc4py.PETSc.KSP` solvers is equal to the number of integration points divided by the number of partitions. This value is halved in the case of real matrices with a region centered at the real axis.

    See also

    `setCISSSizes`, `PEPCISSGetKSPs`

    Source code at slepc4py/SLEPc/PEP.pyx:2926

  getCISSRefinement()

    Get the values of various refinement parameters in the CISS solver.

    Not collective.

    Returns:

      - inner (`int`) – Number of iterative refinement iterations (inner loop).

      - blsize (`int`) – Number of iterative refinement iterations (blocksize loop).

    Return type:

      tuple[int, int]

    See also

    `setCISSRefinement`, `PEPCISSGetRefinement`

    Source code at slepc4py/SLEPc/PEP.pyx:2904

  getCISSSizes()

    Get the values of various size parameters in the CISS solver.

    Not collective.

    Returns:

      - ip (`int`) – Number of integration points.

      - bs (`int`) – Block size.

      - ms (`int`) – Moment size.

      - npart (`int`) – Number of partitions when splitting the communicator.

      - bsmax (`int`) – Maximum block size.

      - realmats (`bool`) – `True` if A and B are real.

    Return type:

      tuple[int, int, int, int, int, bool]

    See also

    `setCISSSizes`, `PEPCISSGetSizes`

    Source code at slepc4py/SLEPc/PEP.pyx:2802

  getCISSThreshold()

    Get the values of various threshold parameters in the CISS solver.

    Not collective.

    Returns:

      - delta (`float`) – Threshold for numerical rank.

      - spur (`float`) – Spurious threshold (to discard spurious eigenpairs.

    Return type:

      tuple[float, float]

    See also

    `setCISSThreshold`, `PEPCISSGetThreshold`

    Source code at slepc4py/SLEPc/PEP.pyx:2859

  getConverged()

    Get the number of converged eigenpairs.

    Not collective.

    Returns:

      nconv – Number of converged eigenpairs.

    Return type:

      `int`

    Notes

    This function should be called after `solve()` has finished.

    The value `nconv` may be different from the number of requested solutions `nev`, but not larger than `ncv`, see `setDimensions()`.

    See also

    `setDimensions`, `solve`, `getEigenpair`, `PEPGetConverged`

    Source code at slepc4py/SLEPc/PEP.pyx:1689

  getConvergedReason()

    Get the reason why the `solve()` iteration was stopped.

    Not collective.

    Returns:

      Negative value indicates diverged, positive value converged.

    Return type:

      `ConvergedReason`

    See also

    `setTolerances`, `solve`, `PEPGetConvergedReason`

    Source code at slepc4py/SLEPc/PEP.pyx:1670

  getConvergenceTest()

    Get the method used to compute the error estimate used in the convergence test.

    Not collective.

    Returns:

      The method used to compute the error estimate used in the convergence test.

    Return type:

      `Conv`

    See also

    `setConvergenceTest`, `PEPGetConvergenceTest`

    Source code at slepc4py/SLEPc/PEP.pyx:820

  getDS()

    Get the direct solver associated to the eigensolver.

    Not collective.

    Returns:

      The direct solver context.

    Return type:

      `DS`

    See also

    `setDS`, `PEPGetDS`

    Source code at slepc4py/SLEPc/PEP.pyx:1324

  getDimensions()

    Get the number of eigenvalues to compute and the dimension of the subspace.

    Not collective.

    Returns:

      - nev (`int`) – Number of eigenvalues to compute.

      - ncv (`int`) – Maximum dimension of the subspace to be used by the solver.

      - mpd (`int`) – Maximum dimension allowed for the projected problem.

    Return type:

      tuple[int, int, int]

    See also

    `setDimensions`, `PEPGetDimensions`

    Source code at slepc4py/SLEPc/PEP.pyx:1038

  getEigenpair(i, Vr=None, Vi=None)

    Get the i-th solution of the eigenproblem as computed by `solve()`.

    Collective.

    The solution consists of both the eigenvalue and the eigenvector.

    Parameters:

      - i (int) – Index of the solution to be obtained.

      - Vr (Vec | None) – Placeholder for the returned eigenvector (real part).

      - Vi (Vec | None) – Placeholder for the returned eigenvector (imaginary part).

    Returns:

      The computed eigenvalue.

    Return type:

      `complex`

    Notes

    The index `i` should be a value between `0` and `nconv-1` (see `getConverged()`). Eigenpairs are indexed according to the ordering criterion established with `setWhichEigenpairs()`.

    The eigenvector is normalized to have unit norm.

    See also

    `solve`, `getConverged`, `setWhichEigenpairs`, `PEPGetEigenpair`

    Source code at slepc4py/SLEPc/PEP.pyx:1715

  getEigenvalueComparison()

    Get the eigenvalue comparison function.

    Not collective.

    Returns:

      The eigenvalue comparison function.

    Return type:

      `PEPEigenvalueComparison`

    See also

    `setEigenvalueComparison`

    Source code at slepc4py/SLEPc/PEP.pyx:1530

  getErrorEstimate(i)

    Get the error estimate associated to the i-th computed eigenpair.

    Not collective.

    Parameters:

      i (int) – Index of the solution to be considered.

    Returns:

      Error estimate.

    Return type:

      `float`

    Notes

    This is the error estimate used internally by the eigensolver. The actual error bound can be computed with `computeError()`.

    See also

    `computeError`, `PEPGetErrorEstimate`

    Source code at slepc4py/SLEPc/PEP.pyx:1756

  getExtract()

    Get the extraction technique used by the `PEP` object.

    Not collective.

    Returns:

      The extraction strategy.

    Return type:

      `Extract`

    See also

    `setExtract`, `PEPGetExtract`

    Source code at slepc4py/SLEPc/PEP.pyx:979

  getInterval()

    Get the computational interval for spectrum slicing.

    Not collective.

    Returns:

      - inta (`float`) – The left end of the interval.

      - intb (`float`) – The right end of the interval.

    Return type:

      tuple[float, float]

    Notes

    If the interval was not set by the user, then zeros are returned.

    See also

    `setInterval`, `PEPGetInterval`

    Source code at slepc4py/SLEPc/PEP.pyx:764

  getIterationNumber()

    Get the current iteration number.

    Not collective.

    If the call to `solve()` is complete, then it returns the number of iterations carried out by the solution method.

    Returns:

      Iteration number.

    Return type:

      `int`

    See also

    `getConvergedReason`, `setTolerances`, `PEPGetIterationNumber`

    Source code at slepc4py/SLEPc/PEP.pyx:1648

  getJDFix()

    Get threshold for changing the target in the correction equation.

    Not collective.

    Returns:

      The threshold for changing the target.

    Return type:

      `float`

    See also

    `setJDFix`, `PEPJDGetFix`

    Source code at slepc4py/SLEPc/PEP.pyx:2566

  getJDMinimalityIndex()

    Get the maximum allowed value of the minimality index.

    Not collective.

    Returns:

      The maximum minimality index.

    Return type:

      `int`

    See also

    `setJDMinimalityIndex`, `PEPJDGetMinimalityIndex`

    Source code at slepc4py/SLEPc/PEP.pyx:2653

  getJDProjection()

    Get the type of projection to be used in the Jacobi-Davidson solver.

    Not collective.

    Returns:

      The type of projection.

    Return type:

      `JDProjection`

    See also

    `setJDProjection`, `PEPJDGetProjection`

    Source code at slepc4py/SLEPc/PEP.pyx:2690

  getJDRestart()

    Get the restart parameter used in the Jacobi-Davidson method.

    Not collective.

    Returns:

      The number of vectors to be kept at restart.

    Return type:

      `float`

    See also

    `setJDRestart`, `PEPJDGetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2523

  getJDReusePreconditioner()

    Get the flag for reusing the preconditioner.

    Not collective.

    Returns:

      The reuse flag.

    Return type:

      `bool`

    See also

    `setJDReusePreconditioner`, `PEPJDGetReusePreconditioner`

    Source code at slepc4py/SLEPc/PEP.pyx:2610

  getLinearEPS()

    Get the eigensolver object associated to the polynomial eigenvalue solver.

    Collective.

    Returns:

      The linear eigensolver.

    Return type:

      `EPS`

    See also

    `setLinearEPS`, `PEPLinearGetEPS`

    Source code at slepc4py/SLEPc/PEP.pyx:1912

  getLinearExplicitMatrix()

    Get if the matrices for the linearization are built explicitly.

    Not collective.

    Returns:

      Boolean flag indicating if the matrices are built explicitly.

    Return type:

      `bool`

    See also

    `getLinearExplicitMatrix`, `PEPLinearSetExplicitMatrix`

    Source code at slepc4py/SLEPc/PEP.pyx:1993

  getLinearLinearization()

    Get the coeffs. defining the linearization of a quadratic eigenproblem.

    Not collective.

    Returns:

      - alpha (`float`) – First parameter of the linearization.

      - beta (`float`) – Second parameter of the linearization.

    Return type:

      tuple[float, float]

    See also

    `setLinearLinearization`, `PEPLinearGetLinearization`

    Source code at slepc4py/SLEPc/PEP.pyx:1953

  getMonitor()

    Get the list of monitor functions.

    Not collective.

    Returns:

      The list of monitor functions.

    Return type:

      `PEPMonitorFunction`

    See also

    `setMonitor`

    Source code at slepc4py/SLEPc/PEP.pyx:1572

  getOperators()

    Get the matrices associated with the eigenvalue problem.

    Collective.

    Returns:

      The matrices associated with the eigensystem.

    Return type:

      `list` of `petsc4py.PETSc.Mat`

    See also

    `setOperators`, `PEPGetOperators`

    Source code at slepc4py/SLEPc/PEP.pyx:1361

  getOptionsPrefix()

    Get the prefix used for searching for all PEP options in the database.

    Not collective.

    Returns:

      The prefix string set for this PEP object.

    Return type:

      `str`

    See also

    `setOptionsPrefix`, `appendOptionsPrefix`, `PEPGetOptionsPrefix`

    Source code at slepc4py/SLEPc/PEP.pyx:417

  getProblemType()

    Get the problem type from the PEP object.

    Not collective.

    Returns:

      The problem type that was previously set.

    Return type:

      `ProblemType`

    See also

    `setProblemType`, `PEPGetProblemType`

    Source code at slepc4py/SLEPc/PEP.pyx:553

  getQArnoldiLocking()

    Get the locking flag used in the Q-Arnoldi method.

    Not collective.

    Returns:

      The locking flag.

    Return type:

      `bool`

    See also

    `setQArnoldiLocking`, `PEPQArnoldiGetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2084

  getQArnoldiRestart()

    Get the restart parameter used in the Q-Arnoldi method.

    Not collective.

    Returns:

      The number of vectors to be kept at restart.

    Return type:

      `float`

    See also

    `setQArnoldiRestart`, `PEPQArnoldiGetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2040

  getRG()

    Get the region object associated to the eigensolver.

    Not collective.

    Returns:

      The region context.

    Return type:

      `RG`

    See also

    `setRG`, `PEPGetRG`

    Source code at slepc4py/SLEPc/PEP.pyx:1287

  getRefine()

    Get the refinement strategy used by the PEP object.

    Not collective.

    Returns:

      - ref (`Refine`) – The refinement type.

      - npart (`int`) – The number of partitions of the communicator.

      - tol (`float`) – The convergence tolerance.

      - its (`int`) – The maximum number of refinement iterations.

      - scheme (`RefineScheme`) – Scheme for solving linear systems.

    Return type:

      tuple[Refine, int, float, int, RefineScheme]

    See also

    `setRefine`, `PEPGetRefine`

    Source code at slepc4py/SLEPc/PEP.pyx:859

  getRefineKSP()

    Get the `KSP` object used by the eigensolver in the refinement phase.

    Collective.

    Returns:

      The linear solver object.

    Return type:

      `petsc4py.PETSc.KSP`

    See also

    `setRefine`, `PEPRefineGetKSP`

    Source code at slepc4py/SLEPc/PEP.pyx:934

  getST()

    Get the spectral transformation object associated to the eigensolver.

    Not collective.

    Returns:

      The spectral transformation.

    Return type:

      `ST`

    See also

    `setST`, `PEPGetST`

    Source code at slepc4py/SLEPc/PEP.pyx:1114

  getSTOARCheckEigenvalueType()

    Get the flag for the eigenvalue type check in spectrum slicing.

    Not collective.

    Returns:

      Whether the eigenvalue type is checked or not.

    Return type:

      `bool`

    See also

    `setSTOARCheckEigenvalueType`, `PEPSTOARGetCheckEigenvalueType`

    Source code at slepc4py/SLEPc/PEP.pyx:2476

  getSTOARDetectZeros()

    Get the flag that enforces zero detection in spectrum slicing.

    Not collective.

    Returns:

      The zero detection flag.

    Return type:

      `bool`

    See also

    `setSTOARDetectZeros`, `PEPSTOARGetDetectZeros`

    Source code at slepc4py/SLEPc/PEP.pyx:2316

  getSTOARDimensions()

    Get the dimensions used for each subsolve step.

    Not collective.

    Returns:

      - nev (`int`) – Number of eigenvalues to compute.

      - ncv (`int`) – Maximum dimension of the subspace to be used by the solver.

      - mpd (`int`) – Maximum dimension allowed for the projected problem.

    Return type:

      tuple[int, int, int]

    See also

    `setSTOARDimensions`, `PEPSTOARGetDimensions`

    Source code at slepc4py/SLEPc/PEP.pyx:2375

  getSTOARInertias()

    Get the values of the shifts and their corresponding inertias.

    Not collective.

    Get the values of the shifts and their corresponding inertias in case of doing spectrum slicing for a computational interval.

    Returns:

      - shifts (`ArrayReal`) – The values of the shifts used internally in the solver.

      - inertias (`ArrayInt`) – The values of the inertia in each shift.

    Return type:

      tuple[ArrayReal, ArrayInt]

    Notes

    This call makes sense only for spectrum slicing runs, that is, when an interval has been given with `setInterval()` and `SINVERT` is set.

    If called after `solve()`, all shifts used internally by the solver are returned (including both endpoints and any intermediate ones). If called before `solve()` and after `setUp()` then only the information of the endpoints of subintervals is available.

    See also

    `setInterval`, `PEPSTOARGetInertias`

    Source code at slepc4py/SLEPc/PEP.pyx:2400

  getSTOARLinearization()

    Get the coefficients that define the linearization of a quadratic eigenproblem.

    Not collective.

    Returns:

      - alpha (`float`) – First parameter of the linearization.

      - beta (`float`) – Second parameter of the linearization.

    Return type:

      tuple[float, float]

    See also

    `setSTOARLinearization`, `PEPSTOARGetLinearization`

    Source code at slepc4py/SLEPc/PEP.pyx:2217

  getSTOARLocking()

    Get the locking flag used in the STOAR method.

    Not collective.

    Returns:

      The locking flag.

    Return type:

      `bool`

    See also

    `setSTOARLocking`, `PEPSTOARGetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2264

  getScale(Dl=None, Dr=None)

    Get the strategy used for scaling the polynomial eigenproblem.

    Not collective.

    Parameters:

      - Dl (petsc4py.PETSc.Vec | None) – Placeholder for the returned left diagonal matrix.

      - Dr (petsc4py.PETSc.Vec | None) – Placeholder for the returned right diagonal matrix.

    Returns:

      - scale (`Scale`) – The scaling strategy.

      - alpha (`float`) – The scaling factor.

      - its (`int`) – The number of iterations of diagonal scaling.

      - lbda (`float`) – Approximation of the wanted eigenvalues (modulus).

    Return type:

      tuple[Scale, float, int, float]

    See also

    `setScale`, `PEPGetScale`

    Source code at slepc4py/SLEPc/PEP.pyx:1151

  getStoppingTest()

    Get the stopping test function.

    Not collective.

    Returns:

      The stopping test function.

    Return type:

      `PEPStoppingFunction`

    See also

    `setStoppingTest`

    Source code at slepc4py/SLEPc/PEP.pyx:1483

  getTOARLocking()

    Get the locking flag used in the TOAR method.

    Not collective.

    Returns:

      The locking flag.

    Return type:

      `bool`

    See also

    `setTOARLocking`, `PEPTOARGetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2175

  getTOARRestart()

    Get the restart parameter used in the TOAR method.

    Not collective.

    Returns:

      The number of vectors to be kept at restart.

    Return type:

      `float`

    See also

    `setTOARRestart`, `PEPTOARGetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2131

  getTarget()

    Get the value of the target.

    Not collective.

    Returns:

      The value of the target.

    Return type:

      `Scalar`

    Notes

    If the target was not set by the user, then zero is returned.

    See also

    `setTarget`, `PEPGetTarget`

    Source code at slepc4py/SLEPc/PEP.pyx:658

  getTolerances()

    Get the tolerance and maximum iteration count.

    Not collective.

    Get the tolerance and maximum iteration count used by the default PEP convergence tests.

    Returns:

      - tol (`float`) – The convergence tolerance.

      - max_it (`int`) – The maximum number of iterations.

    Return type:

      tuple[float, int]

    See also

    `setTolerances`, `PEPGetTolerances`

    Source code at slepc4py/SLEPc/PEP.pyx:708

  getTrackAll()

    Get the flag indicating whether all residual norms must be computed.

    Not collective.

    Returns:

      Whether the solver computes all residuals or not.

    Return type:

      `bool`

    See also

    `setTrackAll`, `PEPGetTrackAll`

    Source code at slepc4py/SLEPc/PEP.pyx:998

  getType()

    Get the PEP type of this object.

    Not collective.

    Returns:

      The solver currently being used.

    Return type:

      `str`

    See also

    `setType`, `PEPGetType`

    Source code at slepc4py/SLEPc/PEP.pyx:398

  getWhichEigenpairs()

    Get which portion of the spectrum is to be sought.

    Not collective.

    Returns:

      The portion of the spectrum to be sought by the solver.

    Return type:

      `Which`

    See also

    `setWhichEigenpairs`, `PEPGetWhichEigenpairs`

    Source code at slepc4py/SLEPc/PEP.pyx:602

  reset()

    Reset the PEP object.

    Collective.

    See also

    `PEPReset`

    Source code at slepc4py/SLEPc/PEP.pyx:338

    Return type:

      None

  setBV(bv)

    Set a basis vectors object associated to the eigensolver.

    Collective.

    Parameters:

      bv (BV) – The basis vectors context.

    Return type:

      None

    See also

    `getBV`, `PEPSetBV`

    Source code at slepc4py/SLEPc/PEP.pyx:1270

  setBasis(basis)

    Set the type of polynomial basis used.

    Logically collective.

    Set the type of polynomial basis used to describe the polynomial eigenvalue problem.

    Parameters:

      basis (Basis) – The basis to be set.

    Return type:

      None

    Notes

    By default, the coefficient matrices passed via `setOperators()` are expressed in the monomial basis, i.e. \(P(\lambda)=A_0+\lambda A_1+\lambda^2 A_2+\dots+\lambda^d A_d\). Other polynomial bases may have better numerical behavior, but the user must then pass the coefficient matrices accordingly.

    See also

    `getBasis`, `setOperators`, `PEPSetBasis`

    Source code at slepc4py/SLEPc/PEP.pyx:524

  setCISSExtraction(extraction)

    Set the extraction technique used in the CISS solver.

    Logically collective.

    Parameters:

      extraction (CISSExtraction) – The extraction technique.

    Return type:

      None

    See also

    `getCISSExtraction`, `PEPCISSSetExtraction`

    Source code at slepc4py/SLEPc/PEP.pyx:2711

  setCISSRefinement(inner=None, blsize=None)

    Set the values of various refinement parameters in the CISS solver.

    Logically collective.

    Parameters:

      - inner (int | None) – Number of iterative refinement iterations (inner loop).

      - blsize (int | None) – Number of iterative refinement iterations (blocksize loop).

    Return type:

      None

    See also

    `getCISSRefinement`, `PEPCISSSetRefinement`

    Source code at slepc4py/SLEPc/PEP.pyx:2881

  setCISSSizes(ip=None, bs=None, ms=None, npart=None, bsmax=None, realmats=False)

    Set the values of various size parameters in the CISS solver.

    Logically collective.

    Parameters:

      - ip (int | None) – Number of integration points.

      - bs (int | None) – Block size.

      - ms (int | None) – Moment size.

      - npart (int | None) – Number of partitions when splitting the communicator.

      - bsmax (int | None) – Maximum block size.

      - realmats (bool) – `True` if A and B are real.

    Return type:

      None

    Notes

    The default number of partitions is 1. This means the internal `petsc4py.PETSc.KSP` object is shared among all processes of the `PEP` communicator. Otherwise, the communicator is split into `npart` communicators, so that `npart` `petsc4py.PETSc.KSP` solves proceed simultaneously.

    See also

    `getCISSSizes`, `setCISSThreshold`, `setCISSRefinement`, `PEPCISSSetSizes`

    Source code at slepc4py/SLEPc/PEP.pyx:2748

  setCISSThreshold(delta=None, spur=None)

    Set the values of various threshold parameters in the CISS solver.

    Logically collective.

    Parameters:

      - delta (float | None) – Threshold for numerical rank.

      - spur (float | None) – Spurious threshold (to discard spurious eigenpairs).

    Return type:

      None

    See also

    `getCISSThreshold`, `PEPCISSSetThreshold`

    Source code at slepc4py/SLEPc/PEP.pyx:2836

  setConvergenceTest(conv)

    Set how to compute the error estimate used in the convergence test.

    Logically collective.

    Parameters:

      conv (Conv) – The method used to compute the error estimate used in the convergence test.

    Return type:

      None

    See also

    `getConvergenceTest`, `PEPSetConvergenceTest`

    Source code at slepc4py/SLEPc/PEP.pyx:840

  setDS(ds)

    Set a direct solver object associated to the eigensolver.

    Collective.

    Parameters:

      ds (DS) – The direct solver context.

    Return type:

      None

    See also

    `getDS`, `PEPSetDS`

    Source code at slepc4py/SLEPc/PEP.pyx:1344

  setDimensions(nev=None, ncv=None, mpd=None)

    Set the number of eigenvalues to compute and the dimension of the subspace.

    Logically collective.

    Parameters:

      - nev (int | None) – Number of eigenvalues to compute.

      - ncv (int | None) – Maximum dimension of the subspace to be used by the solver.

      - mpd (int | None) – Maximum dimension allowed for the projected problem.

    Return type:

      None

    Notes

    Use `DETERMINE` for `ncv` and `mpd` to assign a reasonably good value, which is dependent on the solution method.

    The parameters `ncv` and `mpd` are intimately related, so that the user is advised to set one of them at most. Normal usage is the following:

    - In cases where `nev` is small, the user sets `ncv` (a reasonable default is 2 * `nev`).

    - In cases where `nev` is large, the user sets `mpd`.

    The value of `ncv` should always be between `nev` and (`nev` + `mpd`), typically `ncv` = `nev` + `mpd`. If `nev` is not too large, `mpd` = `nev` is a reasonable choice, otherwise a smaller value should be used.

    See also

    `getDimensions`, `PEPSetDimensions`

    Source code at slepc4py/SLEPc/PEP.pyx:1063

  setEigenvalueComparison(comparison, args=None, kargs=None)

    Set an eigenvalue comparison function.

    Logically collective.

    Notes

    This eigenvalue comparison function is used when `setWhichEigenpairs()` is set to `PEP.Which.USER`.

    See also

    `getEigenvalueComparison`, `PEPSetEigenvalueComparison`

    Source code at slepc4py/SLEPc/PEP.pyx:1500

    Parameters:

      - comparison (PEPEigenvalueComparison | None)

      - args (tuple[Any, ...] | None)

      - kargs (dict[str, Any] | None)

    Return type:

      None

  setExtract(extract)

    Set the extraction strategy to be used.

    Logically collective.

    Parameters:

      extract (Extract) – The extraction strategy.

    Return type:

      None

    Notes

    This is relevant for solvers based on linearization. Once the solver has converged, the polynomial eigenvectors can be extracted from the eigenvectors of the linearized problem in different ways.

    See also

    `getExtract`, `PEPSetExtract`

    Source code at slepc4py/SLEPc/PEP.pyx:954

  setFromOptions()

    Set PEP options from the options database.

    Collective.

    Notes

    To see all options, run your program with the `-help` option.

    This routine must be called before `setUp()` if the user is to be allowed to set the solver type.

    See also

    `setOptionsPrefix`, `PEPSetFromOptions`

    Source code at slepc4py/SLEPc/PEP.pyx:486

    Return type:

      None

  setInitialSpace(space)

    Set the initial space from which the eigensolver starts to iterate.

    Collective.

    Parameters:

      space (Vec | list[Vec]) – The initial space.

    Return type:

      None

    Notes

    Some solvers start to iterate on a single vector (initial vector). In that case, only the first vector is taken into account and the other vectors are ignored.

    These vectors do not persist from one `solve()` call to the other, so the initial space should be set every time.

    The vectors do not need to be mutually orthonormal, since they are explicitly orthonormalized internally.

    Common usage of this function is when the user can provide a rough approximation of the wanted eigenspace. Then, convergence may be faster.

    See also

    `setUp`, `PEPSetInitialSpace`

    Source code at slepc4py/SLEPc/PEP.pyx:1420

  setInterval(inta, intb)

    Set the computational interval for spectrum slicing.

    Logically collective.

    Parameters:

      - inta (float) – The left end of the interval.

      - intb (float) – The right end of the interval.

    Return type:

      None

    Notes

    Spectrum slicing is a technique employed for computing all eigenvalues of symmetric quadratic eigenproblems in a given interval. This function provides the interval to be considered. It must be used in combination with `PEP.Which.ALL`, see `setWhichEigenpairs()`. Note that in polynomial eigenproblems spectrum slicing is implemented in `STOAR` only.

    See also

    `getInterval`, `PEPSetInterval`

    Source code at slepc4py/SLEPc/PEP.pyx:790

  setJDFix(fix)

    Set the threshold for changing the target in the correction equation.

    Logically collective.

    Parameters:

      fix (float) – Threshold for changing the target.

    Return type:

      None

    Notes

    The target in the correction equation is fixed at the first iterations. When the norm of the residual vector is lower than the fix value, the target is set to the corresponding eigenvalue.

    See also

    `getJDFix`, `PEPJDSetFix`

    Source code at slepc4py/SLEPc/PEP.pyx:2542

  setJDMinimalityIndex(flag)

    Set the maximum allowed value for the minimality index.

    Logically collective.

    Parameters:

      flag (int) – The maximum minimality index.

    Return type:

      None

    Notes

    The default value is equal to the degree of the polynomial. A smaller value can be used if the wanted eigenvectors are known to be linearly independent.

    See also

    `getJDMinimalityIndex`, `PEPJDSetMinimalityIndex`

    Source code at slepc4py/SLEPc/PEP.pyx:2629

  setJDProjection(proj)

    Set the type of projection to be used in the Jacobi-Davidson solver.

    Logically collective.

    Parameters:

      proj (JDProjection) – The type of projection.

    Return type:

      None

    See also

    `getJDProjection`, `PEPJDSetProjection`

    Source code at slepc4py/SLEPc/PEP.pyx:2672

  setJDRestart(keep)

    Set the restart parameter for the Jacobi-Davidson method.

    Logically collective.

    Set the restart parameter for the Jacobi-Davidson method, in particular the proportion of basis vectors that must be kept after restart.

    Parameters:

      keep (float) – The number of vectors to be kept at restart.

    Return type:

      None

    Notes

    Allowed values are in the range [0.1,0.9]. The default is 0.5.

    See also

    `getJDRestart`, `PEPJDSetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2497

  setJDReusePreconditioner(flag)

    Set a flag indicating whether the preconditioner must be reused or not.

    Logically collective.

    Parameters:

      flag (bool) – The reuse flag.

    Return type:

      None

    Notes

    The default value is `False`. If set to `True`, the preconditioner is built only at the beginning, using the target value. Otherwise, it may be rebuilt (depending on the `fix` parameter) at each iteration from the Ritz value.

    See also

    `setJDFix`, `getJDReusePreconditioner`, `PEPJDSetReusePreconditioner`

    Source code at slepc4py/SLEPc/PEP.pyx:2585

  setLinearEPS(eps)

    Set an eigensolver object associated to the polynomial eigenvalue solver.

    Collective.

    Parameters:

      eps (EPS) – The linear eigensolver.

    Return type:

      None

    See also

    `getLinearEPS`, `PEPLinearSetEPS`

    Source code at slepc4py/SLEPc/PEP.pyx:1895

  setLinearExplicitMatrix(flag)

    Set flag to explicitly build the matrices for the linearization.

    Logically collective.

    Parameters:

      flag (bool) – Boolean flag indicating if the matrices are built explicitly.

    Return type:

      None

    See also

    `getLinearExplicitMatrix`, `PEPLinearSetExplicitMatrix`

    Source code at slepc4py/SLEPc/PEP.pyx:1975

  setLinearLinearization(alpha=1.0, beta=0.0)

    Set the coefficients that define the linearization of a quadratic eigenproblem.

    Logically collective.

    Parameters:

      - alpha (float) – First parameter of the linearization.

      - beta (float) – Second parameter of the linearization.

    Return type:

      None

    See also

    `getLinearLinearization`, `PEPLinearSetLinearization`

    Source code at slepc4py/SLEPc/PEP.pyx:1932

  setMonitor(monitor, args=None, kargs=None)

    Append a monitor function to the list of monitors.

    Logically collective.

    See also

    `getMonitor`, `cancelMonitor`, `PEPMonitorSet`

    Source code at slepc4py/SLEPc/PEP.pyx:1547

    Parameters:

      - monitor (PEPMonitorFunction | None)

      - args (tuple[Any, ...] | None)

      - kargs (dict[str, Any] | None)

    Return type:

      None

  setOperators(operators)

    Set the matrices associated with the eigenvalue problem.

    Collective.

    Parameters:

      operators (list[Mat]) – The matrices associated with the eigensystem.

    Return type:

      None

    Notes

    The polynomial eigenproblem is defined as \(P(\lambda)x=0\), where \(\lambda\) is the eigenvalue, \(x\) is the eigenvector, and \(P\) is defined as \(P(\lambda) = A_0 + \lambda A_1 + \dots + \lambda^d A_d\), with \(d\) = `nmat`-1 (the degree of \(P\)). For non-monomial bases, this expression is different.

    See also

    `getOperators`, `PEPSetOperators`

    Source code at slepc4py/SLEPc/PEP.pyx:1387

  setOptionsPrefix(prefix=None)

    Set the prefix used for searching for all PEP options in the database.

    Logically collective.

    Parameters:

      prefix (str | None) – The prefix string to prepend to all PEP option requests.

    Return type:

      None

    Notes

    A hyphen (-) must NOT be given at the beginning of the prefix name. The first character of all runtime options is AUTOMATICALLY the hyphen.

    For example, to distinguish between the runtime options for two different PEP contexts, one could call:

        P1.setOptionsPrefix("pep1_")
        P2.setOptionsPrefix("pep2_")

    See also

    `appendOptionsPrefix`, `getOptionsPrefix`, `PEPGetOptionsPrefix`

    Source code at slepc4py/SLEPc/PEP.pyx:436

  setProblemType(problem_type)

    Set the type of the polynomial eigenvalue problem.

    Logically collective.

    Parameters:

      problem_type (ProblemType) – The problem type to be set.

    Return type:

      None

    Notes

    This function is used to instruct SLEPc to exploit certain structure in the polynomial eigenproblem. By default, no particular structure is assumed.

    If the problem matrices are Hermitian (symmetric in the real case) or Hermitian/skew-Hermitian then the solver can exploit this fact to perform less operations or provide better stability. Hyperbolic problems are a particular case of Hermitian problems, some solvers may treat them simply as Hermitian.

    See also

    `setOperators`, `setType`, `getProblemType`, `PEPSetProblemType`

    Source code at slepc4py/SLEPc/PEP.pyx:572

  setQArnoldiLocking(lock)

    Toggle between locking and non-locking variants of the Q-Arnoldi method.

    Logically collective.

    Parameters:

      lock (bool) – `True` if the locking variant must be selected.

    Return type:

      None

    Notes

    The default is to lock converged eigenpairs when the method restarts. This behavior can be changed so that all directions are kept in the working subspace even if already converged to working accuracy (the non-locking variant).

    See also

    `getQArnoldiLocking`, `PEPQArnoldiSetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2059

  setQArnoldiRestart(keep)

    Set the restart parameter for the Q-Arnoldi method.

    Logically collective.

    Set the restart parameter for the Q-Arnoldi method, in particular the proportion of basis vectors that must be kept after restart.

    Parameters:

      keep (float) – The number of vectors to be kept at restart.

    Return type:

      None

    Notes

    Allowed values are in the range [0.1,0.9]. The default is 0.5.

    See also

    `getQArnoldiRestart`, `PEPQArnoldiSetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2014

  setRG(rg)

    Set a region object associated to the eigensolver.

    Collective.

    Parameters:

      rg (RG) – The region context.

    Return type:

      None

    See also

    `getRG`, `PEPSetRG`

    Source code at slepc4py/SLEPc/PEP.pyx:1307

  setRefine(ref, npart=None, tol=None, its=None, scheme=None)

    Set the refinement strategy used by the PEP object.

    Logically collective.

    Set the refinement strategy used by the PEP object, and the associated parameters.

    Parameters:

      - ref (Refine) – The refinement type.

      - npart (int | None) – The number of partitions of the communicator.

      - tol (float | None) – The convergence tolerance.

      - its (int | None) – The maximum number of refinement iterations.

      - scheme (RefineScheme | None) – Scheme for solving linear systems.

    Return type:

      None

    See also

    `getRefine`, `PEPSetRefine`

    Source code at slepc4py/SLEPc/PEP.pyx:890

  setST(st)

    Set a spectral transformation object associated to the eigensolver.

    Collective.

    Parameters:

      st (ST) – The spectral transformation.

    Return type:

      None

    See also

    `getST`, `PEPSetST`

    Source code at slepc4py/SLEPc/PEP.pyx:1134

  setSTOARCheckEigenvalueType(flag)

    Set flag to check if all eigenvalues have the same definite type.

    Logically collective.

    Set a flag to check that all the eigenvalues obtained throughout the spectrum slicing computation have the same definite type.

    Parameters:

      flag (bool) – Whether the eigenvalue type is checked or not.

    Return type:

      None

    Notes

    This option is relevant only for spectrum slicing computations, but is ignored in `slepc4py.SLEPc.PEP.ProblemType.HYPERBOLIC` problems.

    This flag is turned on by default, to guarantee that the computed eigenvalues have the same type (otherwise the computed solution might be wrong). But since the check is computationally quite expensive, the check may be turned off if the user knows for sure that all eigenvalues in the requested interval have the same type.

    See also

    `getSTOARCheckEigenvalueType`, `PEPSTOARSetCheckEigenvalueType`

    Source code at slepc4py/SLEPc/PEP.pyx:2444

  setSTOARDetectZeros(detect)

    Set flag to enforce detection of zeros during the factorizations.

    Logically collective.

    Set a flag to enforce detection of zeros during the factorizations throughout the spectrum slicing computation.

    Parameters:

      detect (bool) – `True` if zeros must checked for.

    Return type:

      None

    Notes

    This call makes sense only for spectrum slicing runs, that is, when an interval has been given with `setInterval()` and `SINVERT` is set.

    A zero in the factorization indicates that a shift coincides with an eigenvalue.

    This flag is turned off by default, and may be necessary in some cases. This feature currently requires an external package for factorizations with support for zero detection, e.g. MUMPS.

    See also

    `setInterval`, `getSTOARDetectZeros`, `PEPSTOARSetDetectZeros`

    Source code at slepc4py/SLEPc/PEP.pyx:2283

  setSTOARDimensions(nev=None, ncv=None, mpd=None)

    Set the dimensions used for each subsolve step.

    Logically collective.

    Parameters:

      - nev (int | None) – Number of eigenvalues to compute.

      - ncv (int | None) – Maximum dimension of the subspace to be used by the solver.

      - mpd (int | None) – Maximum dimension allowed for the projected problem.

    Return type:

      None

    Notes

    This call makes sense only for spectrum slicing runs, that is, when an interval has been given with `setInterval()` and `SINVERT` is set.

    The meaning of the parameters is the same as in `setDimensions()`, but the ones here apply to every subsolve done by the child `PEP` object.

    See also

    `setInterval`, `setDimensions`, `getSTOARDimensions`, `PEPSTOARSetDimensions`

    Source code at slepc4py/SLEPc/PEP.pyx:2335

  setSTOARLinearization(alpha=1.0, beta=0.0)

    Set the coefficients that define the linearization of a quadratic eigenproblem.

    Logically collective.

    Parameters:

      - alpha (float) – First parameter of the linearization.

      - beta (float) – Second parameter of the linearization.

    Return type:

      None

    See also

    `getSTOARLinearization`, `PEPSTOARSetLinearization`

    Source code at slepc4py/SLEPc/PEP.pyx:2196

  setSTOARLocking(lock)

    Toggle between locking and non-locking variants of the STOAR method.

    Logically collective.

    Parameters:

      lock (bool) – `True` if the locking variant must be selected.

    Return type:

      None

    Notes

    The default is to lock converged eigenpairs when the method restarts. This behavior can be changed so that all directions are kept in the working subspace even if already converged to working accuracy (the non-locking variant).

    See also

    `getSTOARLocking`, `PEPSTOARSetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2239

  setScale(scale, alpha=None, Dl=None, Dr=None, its=None, lbda=None)

    Set the scaling strategy to be used.

    Collective.

    Parameters:

      - scale (Scale) – The scaling strategy.

      - alpha (float | None) – The scaling factor.

      - Dl (petsc4py.PETSc.Vec | None) – The left diagonal matrix.

      - Dr (petsc4py.PETSc.Vec | None) – The right diagonal matrix.

      - its (int | None) – The number of iterations of diagonal scaling.

      - lbda (float | None) – Approximation of the wanted eigenvalues (modulus).

    Return type:

      None

    See also

    `getScale`, `PEPSetScale`

    Source code at slepc4py/SLEPc/PEP.pyx:1204

  setStoppingTest(stopping, args=None, kargs=None)

    Set a function to decide when to stop the outer iteration of the eigensolver.

    Logically collective.

    See also

    `getStoppingTest`, `PEPSetStoppingTestFunction`

    Source code at slepc4py/SLEPc/PEP.pyx:1459

    Parameters:

      - stopping (PEPStoppingFunction | None)

      - args (tuple[Any, ...] | None)

      - kargs (dict[str, Any] | None)

    Return type:

      None

  setTOARLocking(lock)

    Toggle between locking and non-locking variants of the TOAR method.

    Logically collective.

    Parameters:

      lock (bool) – `True` if the locking variant must be selected.

    Return type:

      None

    Notes

    The default is to lock converged eigenpairs when the method restarts. This behavior can be changed so that all directions are kept in the working subspace even if already converged to working accuracy (the non-locking variant).

    See also

    `getTOARLocking`, `PEPTOARSetLocking`

    Source code at slepc4py/SLEPc/PEP.pyx:2150

  setTOARRestart(keep)

    Set the restart parameter for the TOAR method.

    Logically collective.

    Set the restart parameter for the TOAR method, in particular the proportion of basis vectors that must be kept after restart.

    Parameters:

      keep (float) – The number of vectors to be kept at restart.

    Return type:

      None

    Notes

    Allowed values are in the range [0.1,0.9]. The default is 0.5.

    See also

    `getTOARRestart`, `PEPTOARSetRestart`

    Source code at slepc4py/SLEPc/PEP.pyx:2105

  setTarget(target)

    Set the value of the target.

    Logically collective.

    Parameters:

      target (Scalar) – The value of the target.

    Return type:

      None

    Notes

    The target is a scalar value used to determine the portion of the spectrum of interest. It is used in combination with `setWhichEigenpairs()`.

    When PETSc is built with real scalars, it is not possible to specify a complex target.

    See also

    `getTarget`, `setWhichEigenpairs`, `PEPSetTarget`

    Source code at slepc4py/SLEPc/PEP.pyx:681

  setTolerances(tol=None, max_it=None)

    Set the tolerance and maximum iteration count.

    Logically collective.

    Set the tolerance and maximum iteration count used by the default PEP convergence tests.

    Parameters:

      - tol (float | None) – The convergence tolerance.

      - max_it (int | None) – The maximum number of iterations

    Return type:

      None

    Notes

    Use `DETERMINE` for `max_it` to assign a reasonably good value, which is dependent on the solution method.

    See also

    `getTolerances`, `PEPSetTolerances`

    Source code at slepc4py/SLEPc/PEP.pyx:733

  setTrackAll(trackall)

    Set flag to compute the residual of all approximate eigenpairs.

    Logically collective.

    Set if the solver must compute the residual of all approximate eigenpairs or not.

    Parameters:

      trackall (bool) – Whether to compute all residuals or not.

    Return type:

      None

    See also

    `getTrackAll`, `PEPSetTrackAll`

    Source code at slepc4py/SLEPc/PEP.pyx:1017

  setType(pep_type)

    Set the particular solver to be used in the PEP object.

    Logically collective.

    Parameters:

      pep_type (Type | str) – The solver to be used.

    Return type:

      None

    Notes

    The default is `TOAR`. Normally, it is best to use `setFromOptions()` and then set the PEP type from the options database rather than by using this routine. Using the options database provides the user with maximum flexibility in evaluating the different available methods.

    See also

    `getType`, `PEPSetType`

    Source code at slepc4py/SLEPc/PEP.pyx:371

  setUp()

    Set up all the internal data structures.

    Collective.

    Notes

    Sets up all the internal data structures necessary for the execution of the eigensolver. This includes the setup of the internal `ST` object.

    This function need not be called explicitly in most cases, since `solve()` calls it. It can be useful when one wants to measure the set-up time separately from the solve time.

    See also

    `solve`, `PEPSetUp`

    Source code at slepc4py/SLEPc/PEP.pyx:1604

    Return type:

      None

  setWhichEigenpairs(which)

    Set which portion of the spectrum is to be sought.

    Logically collective.

    Parameters:

      which (Which) – The portion of the spectrum to be sought by the solver.

    Return type:

      None

    Notes

    Not all eigensolvers implemented in PEP account for all the possible values. Also, some values make sense only for certain types of problems. If SLEPc is compiled for real numbers `PEP.Which.LARGEST_IMAGINARY` and `PEP.Which.SMALLEST_IMAGINARY` use the absolute value of the imaginary part for eigenvalue selection.

    The target is a scalar value provided with `setTarget()`.

    The criterion `PEP.Which.TARGET_IMAGINARY` is available only in case PETSc and SLEPc have been built with complex scalars.

    `PEP.Which.ALL` is intended for use in combination with an interval (see `setInterval()`), when all eigenvalues within the interval are requested, or in the context of the `PEP.Type.CISS` solver for computing all eigenvalues in a region.

    See also

    `getWhichEigenpairs`, `setTarget`, `setInterval`, `PEPSetWhichEigenpairs`

    Source code at slepc4py/SLEPc/PEP.pyx:621

  solve()

    Solve the polynomial eigenproblem.

    Collective.

    Notes

    The problem matrices are specified with `setOperators()`.

    `solve()` will return without generating an error regardless of whether all requested solutions were computed or not. Call `getConverged()` to get the actual number of computed solutions, and `getConvergedReason()` to determine if the solver converged or failed and why.

    See also

    `setUp`, `setOperators`, `getConverged`, `getConvergedReason`, `PEPSolve`

    Source code at slepc4py/SLEPc/PEP.pyx:1626

    Return type:

      None

  valuesView(viewer=None)

    Display the computed eigenvalues in a viewer.

    Collective.

    Parameters:

      viewer (Viewer | None) – Visualization context; if not provided, the standard output is used.

    Return type:

      None

    See also

    `solve`, `vectorsView`, `errorView`, `PEPValuesView`

    Source code at slepc4py/SLEPc/PEP.pyx:1855

  vectorsView(viewer=None)

    Output computed eigenvectors to a viewer.

    Collective.

    Parameters:

      viewer (Viewer | None) – Visualization context; if not provided, the standard output is used.

    Return type:

      None

    See also

    `solve`, `valuesView`, `errorView`, `PEPVectorsView`

    Source code at slepc4py/SLEPc/PEP.pyx:1874

  view(viewer=None)

    Print the PEP data structure.

    Collective.

    Parameters:

      viewer (Viewer | None) – Visualization context; if not provided, the standard output is used.

    Return type:

      None

    See also

    `PEPView`

    Source code at slepc4py/SLEPc/PEP.pyx:305

  Attributes Documentation

  bv

    The basis vectors (`BV`) object associated.

    Source code at slepc4py/SLEPc/PEP.pyx:3011

  ds

    The direct solver (`DS`) object associated.

    Source code at slepc4py/SLEPc/PEP.pyx:3025

  extract

    The type of extraction technique to be employed.

    Source code at slepc4py/SLEPc/PEP.pyx:2976

  max_it

    The maximum iteration count.

    Source code at slepc4py/SLEPc/PEP.pyx:2990

  problem_type

    The type of the eigenvalue problem.

    Source code at slepc4py/SLEPc/PEP.pyx:2955

  rg

    The region (`RG`) object associated.

    Source code at slepc4py/SLEPc/PEP.pyx:3018

  st

    The spectral transformation (`ST`) object associated.

    Source code at slepc4py/SLEPc/PEP.pyx:3004

  target

    The value of the target.

    Source code at slepc4py/SLEPc/PEP.pyx:2969

  tol

    The tolerance.

    Source code at slepc4py/SLEPc/PEP.pyx:2983

  track_all

    Compute the residual norm of all approximate eigenpairs.

    Source code at slepc4py/SLEPc/PEP.pyx:2997

  which

    The portion of the spectrum to be sought.

    Source code at slepc4py/SLEPc/PEP.pyx:2962