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 Parameters#

  • PetscInt nverts - the number of element vertices

  • PetscReal coords[3nverts] -* the physical coordinates of the vertices (in canonical numbering)

  • PetscInt npts - the number of evaluation points (quadrature points)

  • PetscReal quad[3npts] -* the evaluation points (quadrature points) in the reference space

Output Parameters#

  • PetscReal phypts[3npts] -* 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

  • jacobian - jacobian

  • ijacobian - ijacobian

  • volume - volume

Level#

advanced

Location#

src/dm/impls/moab/dmmbfem.cxx

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