# petsc4py.PETSc.KSP.NormType#

class petsc4py.PETSc.KSP.NormType#

Bases: `object`

KSP norm type.

The available norm types are:

`NONE`

Skips computing the norm, this should generally only be used if you are using the Krylov method as a smoother with a fixed small number of iterations. Implicitly sets `KSPConvergedSkip` as KSP convergence test. Note that certain algorithms such as `Type.GMRES` ALWAYS require the norm calculation, for these methods the norms are still computed, they are just not used in the convergence test.

`PRECONDITIONED`

The default for left preconditioned solves, uses the l₂ norm of the preconditioned residual P⁻¹(b - Ax).

`UNPRECONDITIONED`

Uses the l₂ norm of the true b - Ax residual.

`NATURAL`

Attributes Summary

 `DEFAULT` Constant `DEFAULT` of type `int` `NATURAL` Constant `NATURAL` of type `int` `NO` Constant `NO` of type `int` `NONE` Constant `NONE` of type `int` `NORM_DEFAULT` Constant `NORM_DEFAULT` of type `int` `NORM_NATURAL` Constant `NORM_NATURAL` of type `int` `NORM_NONE` Constant `NORM_NONE` of type `int` `NORM_PRECONDITIONED` Constant `NORM_PRECONDITIONED` of type `int` `NORM_UNPRECONDITIONED` Constant `NORM_UNPRECONDITIONED` of type `int` `PRECONDITIONED` Constant `PRECONDITIONED` of type `int` `UNPRECONDITIONED` Constant `UNPRECONDITIONED` of type `int`

Attributes Documentation

DEFAULT: int = DEFAULT#

Constant `DEFAULT` of type `int`

NATURAL: int = NATURAL#

Constant `NATURAL` of type `int`

NO: int = NO#

Constant `NO` of type `int`

NONE: int = NONE#

Constant `NONE` of type `int`

NORM_DEFAULT: int = NORM_DEFAULT#

Constant `NORM_DEFAULT` of type `int`

NORM_NATURAL: int = NORM_NATURAL#

Constant `NORM_NATURAL` of type `int`

NORM_NONE: int = NORM_NONE#

Constant `NORM_NONE` of type `int`

NORM_PRECONDITIONED: int = NORM_PRECONDITIONED#

Constant `NORM_PRECONDITIONED` of type `int`

NORM_UNPRECONDITIONED: int = NORM_UNPRECONDITIONED#

Constant `NORM_UNPRECONDITIONED` of type `int`

PRECONDITIONED: int = PRECONDITIONED#

Constant `PRECONDITIONED` of type `int`

UNPRECONDITIONED: int = UNPRECONDITIONED#

Constant `UNPRECONDITIONED` of type `int`