petsc-3.7.3 2016-07-24
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# TaoGetConvergedReason

Gets the reason the Tao iteration was stopped.

### Synopsis

    #include "petsctao.h"
    PetscErrorCode TaoGetConvergedReason(Tao tao, TaoConvergedReason *reason)

Not Collective

### Input Parameter

tao -the Tao solver context

### Output Parameter

reason -one of

     TAO_CONVERGED_GATOL (3)           ||g(X)|| < gatol

     TAO_CONVERGED_GRTOL (4)           ||g(X)|| / f(X)  < grtol

     TAO_CONVERGED_GTTOL (5)           ||g(X)|| / ||g(X0)|| < gttol

     TAO_CONVERGED_STEPTOL (6)         step size small

     TAO_CONVERGED_MINF (7)            F < F_min

     TAO_CONVERGED_USER (8)            User defined

     TAO_DIVERGED_MAXITS (-2)          its > maxits

     TAO_DIVERGED_NAN (-4)             Numerical problems

     TAO_DIVERGED_MAXFCN (-5)          fevals > max_funcsals

     TAO_DIVERGED_LS_FAILURE (-6)      line search failure

     TAO_DIVERGED_TR_REDUCTION (-7)    trust region failure

     TAO_DIVERGED_USER(-8)             (user defined)

$ TAO_CONTINUE_ITERATING (0)

where

| X | - current solution
| X0 | - initial guess
| f(X) | - current function value
| f(X*) | - true solution (estimated)
| g(X) | - current gradient
| its | - current iterate number
| maxits | - maximum number of iterates
| fevals | - number of function evaluations
| max_funcsals | - maximum number of function evaluations

### See Also

TaoSetConvergenceTest(), TaoSetTolerances()

Level:intermediate
Location: src/tao/interface/taosolver.c
Index of all Tao routines
Table of Contents for all manual pages
Index of all manual pages

### Examples

src/tao/constrained/examples/tutorials/maros.c.html
src/tao/leastsquares/examples/tutorials/chwirut1f.F.html