gf_eltm

This object represents a type of elementary matrix. In order to obtain a numerical value of these matrices, see gf_mesh_im_get(mesh_im MI, 'eltm'). If you have very particular assembling needs, or if you just want to check the content of an elementary matrix, this function might be useful. But the generic assembly abilities of gf_asm(...) should suit most needs.

# Calling Sequence

    E = gf_eltm('base', fem FEM)

    E = gf_eltm('grad', fem FEM)

    E = gf_eltm('hessian', fem FEM)

    E = gf_eltm('normal')

    E = gf_eltm('grad_geotrans')

    E = gf_eltm('grad_geotrans_inv')

    E = gf_eltm('product', eltm A, eltm B)

## Description

General constructor for eltm objects.

This object represents a type of elementary matrix. In order to obtain a numerical value of these matrices, see gf_mesh_im_get(mesh_im MI, 'eltm'). If you have very particular assembling needs, or if you just want to check the content of an elementary matrix, this function might be useful. But the generic assembly abilities of gf_asm(...) should suit most needs.

## Command list

- `E = gf_eltm('base', fem FEM)`

  return a descriptor for the integration of shape functions on elements, using the fem `FEM`.

- `E = gf_eltm('grad', fem FEM)`

  return a descriptor for the integration of the gradient of shape functions on elements, using the fem `FEM`.

- `E = gf_eltm('hessian', fem FEM)`

  return a descriptor for the integration of the hessian of shape functions on elements, using the fem `FEM`.

- `E = gf_eltm('normal')`

  return a descriptor for the unit normal of convex faces.

- `E = gf_eltm('grad_geotrans')`

  return a descriptor to the gradient matrix of the geometric transformation.

- `E = gf_eltm('grad_geotrans_inv')`

  return a descriptor to the inverse of the gradient matrix of the geometric transformation (this is rarely used).

- `E = gf_eltm('product', eltm A, eltm B)`

  return a descriptor for the integration of the tensorial product of elementary matrices `A` and `B`.

## See Also

- getfem types

## Authors

Y. Collette