#include "petscvec.h" PetscErrorCode VecNormAvailable(Vec x,NormType type,PetscBool *available,PetscReal *val)Not Collective
x | - the vector | |
type | - one of NORM_1, NORM_2, NORM_INFINITY. Also available NORM_1_AND_2, which computes both norms and stores them in a two element array. |
available | - PETSC_TRUE if the val returned is valid | |
val | - the norm |
NORM_1 denotes sum_i |x_i|
NORM_2 denotes sqrt(sum_i (x_i)^2)
NORM_INFINITY denotes max_i |x_i|
per-processor memory bandwidth
interprocessor latency
work load inbalance that causes certain processes to arrive much earlier than others