IterativeParams Class¶
-
class
plask.
IterativeParams
¶ Iterative matrix parameters
This class holds parameters for iterative matrix used by solvers implementing Finite Element Method. PLaSK uses NSPCG package for performing iterations. Please refer to its documentation for explanation of most of the settings.
Attributes¶
accelerator |
Solver accelerator |
converged |
True if the solver converged |
err |
Residual error in the last run |
iters |
Number of iterations in the last run |
ltrunc |
Truncation level |
lvfill |
Fill-in level |
maxerr |
Maximum allowed residual iteration |
maxit |
Maximum number of iterations |
ndeg |
Polynomial degree |
nfact |
Frequency of partial factorization |
noconv |
Desired behavior if the iterative solver does not converge. |
nrestart |
Restart frequency |
nsave |
Saved vectors number |
omega |
Relaxation parameter |
preconditioner |
Solver preconditioner |
Descriptions¶
Attribute Details¶
-
IterativeParams.
accelerator
¶ Solver accelerator
This is current iterative matrix solver acceleration algorithm.
Possible 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
-
IterativeParams.
converged
¶ True if the solver converged
-
IterativeParams.
err
¶ Residual error in the last run
-
IterativeParams.
iters
¶ Number of iterations in the last run
-
IterativeParams.
ltrunc
¶ Truncation level
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.
-
IterativeParams.
lvfill
¶ Fill-in level
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.
-
IterativeParams.
maxerr
¶ Maximum allowed residual iteration
-
IterativeParams.
maxit
¶ Maximum number of iterations
-
IterativeParams.
ndeg
¶ Polynomial degree
Degree of the polynomial to be used for the polynomial preconditioners.
-
IterativeParams.
nfact
¶ Frequency of partial factorization
This number initializes the frequency of partial factorizations. It specifies the number of linear system evaluatations between factorizations. The default value is 1, which means that a factorization is performed at every iteration.
-
IterativeParams.
noconv
¶ Desired behavior if the iterative solver does not converge.
Possible choices are:
error
,warning
,continue
-
IterativeParams.
nrestart
¶ Restart frequency
The number of iterations between restarts for restarted acceleration methods.
-
IterativeParams.
nsave
¶ Saved vectors number
The number of old vectors to be saved for the truncated acceleration methods.
-
IterativeParams.
omega
¶ Relaxation parameter
-
IterativeParams.
preconditioner
¶ Solver preconditioner
This is current preconditioner used for iterative matrix solver.
Possible choices:¶ rich
Richardson’s method jac
Jacobi method ljac
Line Jacobi method ljacx
Line Jacobi method (approx. inverse) sor
Successive Overrelaxation (can be used only with SOR accelerator) ssor
Symmetric SOR 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)