PETSc version 3.15.5
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# TaoGetConvergenceHistory

Gets the arrays used to hold the convergence history.

### Synopsis

    #include "petsctao.h"
    PetscErrorCode TaoGetConvergenceHistory(Tao tao, PetscReal **obj, PetscReal **resid, PetscReal **cnorm, PetscInt **lits, PetscInt *nhist)

Collective on Tao

### Input Parameter

| tao | - the Tao context

### Output Parameters

| obj | - array used to hold objective value history
| resid | - array used to hold residual history
| cnorm | - array used to hold constraint violation history
| lits | - integer array used to hold linear solver iteration count
| nhist | - size of obj, resid, cnorm, and lits

### Notes

This routine must be preceded by calls to TaoSetConvergenceHistory() and TaoSolve(), otherwise it returns useless information.

The calling sequence for this routine in Fortran is

      call TaoGetConvergenceHistory(Tao tao, PetscInt nhist, PetscErrorCode ierr)

This routine is useful, e.g., when running a code for purposes of accurate performance monitoring, when no I/O should be done during the section of code that is being timed.

### See Also

TaoSetConvergenceHistory()

### Level

advanced

### Location

src/tao/interface/taosolver.c

### Examples

src/tao/leastsquares/tutorials/chwirut1.c.html
src/tao/leastsquares/tutorials/cs1.c.html
src/tao/leastsquares/tutorials/tomography.c.html
src/tao/leastsquares/tutorials/chwirut1f.F90.html
Index of all Tao routines
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Index of all manual pages