petsc-3.7.6 2017-04-24
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# PetscFEIntegrateResidual

Produce the element residual vector for a chunk of elements by quadrature integration

### Synopsis

#include "petscfe.h"
PetscErrorCode PetscFEIntegrateResidual(PetscFE fem, PetscDS prob, PetscInt field, PetscInt Ne, PetscFECellGeom *geom,
const PetscScalar coefficients[], const PetscScalar coefficients_t[], PetscDS probAux, const PetscScalar coefficientsAux[], PetscScalar elemVec[])

Not collective

### Input Parameters

 fem - The PetscFE object for the field being integrated prob - The PetscDS specifying the discretizations and continuum functions field - The field being integrated Ne - The number of elements in the chunk geom - The cell geometry for each cell in the chunk coefficients - The array of FEM basis coefficients for the elements coefficients_t - The array of FEM basis time derivative coefficients for the elements probAux - The PetscDS specifying the auxiliary discretizations coefficientsAux - The array of FEM auxiliary basis coefficients for the elements

Output Parameter

elemVec -the element residual vectors from each element

### Note

Loop over batch of elements (e):

  Loop over quadrature points (q):

    Make u_q and gradU_q (loops over fields,Nb,Ncomp) and x_q

    Call f_0 and f_1

  Loop over element vector entries (f,fc --> i):

    elemVec[i] += \psi^{fc}_f(q) f0_{fc}(u, \nabla u) + \nabla\psi^{fc}_f(q) \cdot f1_{fc,df}(u, \nabla u)