gf_fem_get

General function for querying information about FEM objects.

# Calling Sequence

    n = gf_fem_get(fem F, 'nbdof'[, int cv])

    d = gf_fem_get(fem F, 'dim')

    td = gf_fem_get(fem F, 'target_dim')

    P = gf_fem_get(fem F, 'pts'[, int cv])

    b = gf_fem_get(fem F, 'is_equivalent')

    b = gf_fem_get(fem F, 'is_lagrange')

    b = gf_fem_get(fem F, 'is_polynomial')

    d = gf_fem_get(fem F, 'estimated_degree')

    E = gf_fem_get(fem F, 'base_value',mat p)

    ED = gf_fem_get(fem F, 'grad_base_value',mat p)

    EH = gf_fem_get(fem F, 'hess_base_value',mat p)

    gf_fem_get(fem F, 'poly_str')

    string = gf_fem_get(fem F, 'char')

    gf_fem_get(fem F, 'display')

## Description

General function for querying information about FEM objects.

## Command list

- `n = gf_fem_get(fem F, 'nbdof'[, int cv])`

  Return the number of dof for the fem. Some specific fem (for example 'interpolated_fem') may require a convex number `cv` to give their result. In most of the case, you can omit this convex number.

- `d = gf_fem_get(fem F, 'dim')`

  Return the dimension (dimension of the reference convex) of the fem.

- `td = gf_fem_get(fem F, 'target_dim')`

  Return the dimension of the target space. The target space dimension is usually 1, except for vector fem.

- `P = gf_fem_get(fem F, 'pts'[, int cv])`

  Get the location of the dof on the reference element. Some specific fem may require a convex number `cv` to give their result (for example 'interpolated_fem'). In most of the case, you can omit this convex number.

- `b = gf_fem_get(fem F, 'is_equivalent')`

  Return 0 if the fem is not equivalent. Equivalent fem are evaluated on the reference convex. This is the case of most classical fem's.

- `b = gf_fem_get(fem F, 'is_lagrange')`

  Return 0 if the fem is not of Lagrange type.

- `b = gf_fem_get(fem F, 'is_polynomial')`

  Return 0 if the basis functions are not polynomials.

- `d = gf_fem_get(fem F, 'estimated_degree')`

  Return an estimation of the polynomial degree of the fem. This is an estimation for fem which are not polynomials.

- `E = gf_fem_get(fem F, 'base_value',mat p)`

  Evaluate all basis functions of the FEM at point `p`. `p` is supposed to be in the reference convex!

- `ED = gf_fem_get(fem F, 'grad_base_value',mat p)`

  Evaluate the gradient of all base functions of the fem at point `p`. `p` is supposed to be in the reference convex!

- `EH = gf_fem_get(fem F, 'hess_base_value',mat p)`

  Evaluate the Hessian of all base functions of the fem at point `p`. `p` is supposed to be in the reference convex!.

- `gf_fem_get(fem F, 'poly_str')`

  Return the polynomial expressions of its basis functions in the reference convex. The result is expressed as a cell array of strings. Of course this will fail on non-polynomial fem's.

- `string = gf_fem_get(fem F, 'char')`

  Ouput a (unique) string representation of the fem. This can be used to perform comparisons between two different fem objects.

- `gf_fem_get(fem F, 'display')`

  displays a short summary for a fem object.

## See Also

- getfem types

## Authors

Y. Collette