petsc-3.11.4 2019-09-28
VecNorm
Computes the vector norm.
Synopsis
#include "petscvec.h"
PetscErrorCode VecNorm(Vec x,NormType type,PetscReal *val)
Collective on Vec
Input Parameters
Output Parameter
val -the norm
Notes
NORM_1 denotes sum_i |x_i|
NORM_2 denotes sqrt(sum_i |x_i|^2)
NORM_INFINITY denotes max_i |x_i|
For complex numbers NORM_1 will return the traditional 1 norm of the 2 norm of the complex numbers; that is the 1
norm of the absolutely values of the complex entries. In PETSc 3.6 and earlier releases it returned the 1 norm of
the 1 norm of the complex entries (what is returned by the BLAS routine asum()). Both are valid norms but most
people expect the former.
Performance Issues
per-processor memory bandwidth
interprocessor latency
work load inbalance that causes certain processes to arrive much earlier than others
See Also
VecDot(), VecTDot(), VecNorm(), VecDotBegin(), VecDotEnd(), VecNormAvailable(),
VecNormBegin(), VecNormEnd()
Level
intermediate
Location
src/vec/vec/interface/rvector.c
Examples
src/vec/vec/examples/tutorials/ex1.c.html
src/vec/vec/examples/tutorials/ex11.c.html
src/vec/vec/examples/tutorials/ex1f.F90.html
src/vec/vec/examples/tutorials/ex1f90.F90.html
src/vec/vec/examples/tutorials/ex11f.F.html
src/vec/vec/examples/tutorials/ex11f90.F90.html
src/vec/vec/examples/tutorials/ex20f90.F90.html
src/mat/examples/tutorials/ex2.c.html
src/mat/examples/tutorials/ex9.c.html
src/dm/impls/stag/examples/tutorials/ex1.c.html
src/dm/impls/stag/examples/tutorials/ex2.c.html
Implementations
VecNorm_MPICUDA in src/vec/vec/impls/mpi/mpicuda/mpicuda.cu
VecNorm_MPIViennaCL in src/vec/vec/impls/mpi/mpiviennacl/mpiviennacl.cxx
VecNorm_MPI in src/vec/vec/impls/mpi/pvec2.c
VecNorm_Nest in src/vec/vec/impls/nest/vecnest.c
VecNorm_Seq in src/vec/vec/impls/seq/bvec2.c
VecNorm_SeqCUDA in src/vec/vec/impls/seq/seqcuda/veccuda2.cu
VecNorm_SeqViennaCL in src/vec/vec/impls/seq/seqviennacl/vecviennacl.cxx
Index of all Vec routines
Table of Contents for all manual pages
Index of all manual pages