KSPComputeConvergenceRate#

Compute the convergence rate for the iteration https:/en.wikipedia.org/wiki/Coefficient_of_determination

Synopsis#

#include "petscksp.h" 
#include "petscmat.h" 
PetscErrorCode KSPComputeConvergenceRate(KSP ksp, PetscReal *cr, PetscReal *rRsq, PetscReal *ce, PetscReal *eRsq)

Not Collective

Input Parameter#

ksp - The KSP

Output Parameters#

cr - The residual contraction rate
rRsq - The coefficient of determination, \(R^2\), indicating the linearity of the data
ce - The error contraction rate
eRsq - The coefficient of determination, \(R^2\), indicating the linearity of the data

Note#

Suppose that the residual is reduced linearly, \(r_k = c^k r_0\), which means \(log r_k = log r_0 + k log c\). After linear regression, the slope is \(\log c\). The coefficient of determination is given by \(1 - \frac{\sum_i (y_i - f(x_i))^2}{\sum_i (y_i - \bar y)}\),

Level#

advanced

Location#

src/ksp/ksp/interface/itfunc.c

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