VecAXPY#

Computes y = alpha x + y.

Synopsis#

#include "petscvec.h"   
PetscErrorCode VecAXPY(Vec y, PetscScalar alpha, Vec x)

Logically Collective

Input Parameters#

alpha - the scalar
x - vector scale by alpha
y - vector accumulated into

Output Parameter#

y - output vector

Notes#

This routine is optimized for alpha of 0.0, otherwise it calls the BLAS routine

    VecAXPY(y,alpha,x)                   y = alpha x           +      y
    VecAYPX(y,beta,x)                    y =       x           + beta y
    VecAXPBY(y,alpha,beta,x)             y = alpha x           + beta y
    VecWAXPY(w,alpha,x,y)                w = alpha x           +      y
    VecAXPBYPCZ(w,alpha,beta,gamma,x,y)  z = alpha x           + beta y + gamma z
    VecMAXPY(y,nv,alpha[],x[])           y = sum alpha[i] x[i] +      y