PetscConvEstGetConvRate#

Returns an estimate of the convergence rate for the discretization

Synopsis#

#include "petscconvest.h" 
PetscErrorCode PetscConvEstGetConvRate(PetscConvEst ce, PetscReal alpha[])

Not Collective

Input Parameter#

Output Parameter#

  • alpha - The convergence rate for each field

Options Database Keys#

  • -snes_convergence_estimate - Execute convergence estimation inside SNESSolve() and print out the rate

  • -ts_convergence_estimate - Execute convergence estimation inside TSSolve() and print out the rate

Notes#

The convergence rate alpha is defined by

|| u_\Delta - u_exact || < C \Delta^alpha

where u_\Delta is the discrete solution, and Delta is a measure of the discretization size. We usually use h for the spatial resolution and \Delta t for the temporal resolution.

We solve a series of problems using increasing resolution (refined meshes or decreased timesteps), calculate an error based upon the exact solution in the PetscDS, and then fit the result to our model above using linear regression.

See Also#

PetscConvEstSetSolver(), PetscConvEstCreate(), SNESSolve(), TSSolve()

Level#

intermediate

Location#

src/snes/utils/convest.c

Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages