petsc-3.14.6 2021-03-30
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Compute_Lagrange_Basis_2D_Internal

Evaluate bases and derivatives at quadrature points for a QUAD4 or TRI3 element.

Synopsis

#include "petscdt.h" 
#include "petscdmmoab.h"   
PetscErrorCode Compute_Lagrange_Basis_2D_Internal(const PetscInt nverts, const PetscReal *coords, const PetscInt npts, const PetscReal *quad, PetscReal *phypts,
                                                  PetscReal *jxw, PetscReal *phi, PetscReal *dphidx, PetscReal *dphidy,
                                                  PetscReal *jacobian, PetscReal *ijacobian, PetscReal *volume)
The routine is given the coordinates of the vertices of a quadrangle or triangle.

The routine evaluates the basis functions associated with each quadrature point provided, and their derivatives with respect to X and Y.

Notes

Example Physical Element (QUAD4)

    4------3        s
    |      |        |
    |      |        |
    |      |        |
    1------2        0-------r

Input Parameter

PetscInt nverts - the number of element vertices
PetscReal coords[3*nverts] - the physical coordinates of the vertices (in canonical numbering)
PetscInt npts - the number of evaluation points (quadrature points)
PetscReal quad[3*npts] - the evaluation points (quadrature points) in the reference space

Output Parameter

PetscReal phypts[3*npts] - the evaluation points (quadrature points) transformed to the physical space
PetscReal jxw[npts] - the jacobian determinant * quadrature weight necessary for assembling discrete contributions
PetscReal phi[npts] - the bases evaluated at the specified quadrature points
PetscReal dphidx[npts] - the derivative of the bases wrt X-direction evaluated at the specified quadrature points
PetscReal dphidy[npts] - the derivative of the bases wrt Y-direction evaluated at the specified quadrature points

Level

advanced

Location

src/dm/impls/moab/dmmbfem.cxx
Index of all DMMOAB routines
Table of Contents for all manual pages
Index of all manual pages