Sets the array used to hold the residual history. If set, this array will contain the residual norms computed at each iteration of the solver.


#include "petscksp.h" 
#include "petscmat.h" 
PetscErrorCode KSPSetResidualHistory(KSP ksp, PetscReal a[], PetscInt na, PetscBool reset)

Not Collective

Input Parameters#

  • ksp - iterative context obtained from KSPCreate()

  • a - array to hold history

  • na - size of a

  • reset - PETSC_TRUE indicates the history counter is reset to zero for each new linear solve


If provided, a is NOT freed by PETSc so the user needs to keep track of it and destroy once the KSP object is destroyed. If β€˜a’ is NULL then space is allocated for the history. If β€˜na’ PETSC_DECIDE or PETSC_DEFAULT then a default array of length 10000 is allocated.

If the array is not long enough then once the iterations is longer than the array length KSPSolve() stops recording the history

See Also#

KSP: Linear System Solvers, KSPGetResidualHistory(), KSP





Index of all KSP routines
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Index of all manual pages