Specify Lagrange elements in the model.shape field of the model object. The constructor of the Lagrange shape function is
shlag. The following properties are allowed:
The Lagrange element defines the following variables. Denote basename with
u, and let
x and
y denote (not necessarily distinct) spatial coordinates. The variables are (
sdim = space dimension and
edim = mesh element dimension):
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ux, meaning the derivative of u with respect to x, defined on edim = sdim
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uxy, meaning a second derivative, defined on edim = sdim
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uTx, the tangential derivative variable, meaning the x-component of the tangential projection of the gradient, defined on edim < sdim
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uTxy, meaning xy-component of the tangential projection of the second derivative, defined when edim < sdim
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Specify serendipity shape functions in the model.shape field of the model object. The constructor of the serendipity shape function is
shnserp. The following properties are allowed:
The nodal serendipity element defines the following field variables. Denote basename with
u, and let
x and
y denote (not necessarily distinct) spatial coordinates. The variables are (
sdim = space dimension and
edim = mesh element dimension):
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ux, meaning the derivative of u with respect to x, defined when edim = sdim or edim=0
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uxy, meaning a second derivative, defined when edim = sdim
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uTx, the tangential derivative variable, meaning the x-component of the tangential projection of the gradient, defined when 0 < edim < sdim
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uTxy, meaning xy-component of the tangential projection of the second derivative, defined when edim < sdim
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Specify Argyris shape functions in the model.shape field of the model object. The constructor of the Argyris shape function is
sharg_2_5. The following properties are allowed:
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ux and uy at corners, meaning derivatives of u
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uxx, uxy, and uyy at corners, meaning second derivatives
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un at side midpoints, meaning a normal derivative. The direction of the normal is to the right if moving along an edge from a corner with lower mesh vertex number to a corner with higher number
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ux, meaning the derivative of u with respect to x
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uxy, meaning a second derivative, defined for edim = sdim and edim = 0
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uxTy, the tangential derivative variable, meaning the y-component of the tangential projection of the gradient of ux, defined for 0 < edim < sdim
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Specify Hermite shape functions in the model.shape field of the model object. The constructor of the Hermite shape function is
shherm. The following properties are allowed:
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The values of the first derivatives of basename with respect to the global spatial coordinates at each corner of the mesh element. The names of these derivatives are formed by appending the spatial coordinate names to basename.
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The Hermite element defines the following field variables. Denote basename with
u, and let
x and
y denote (not necessarily distinct) spatial coordinates. The variables are (
sdim = space dimension and
edim = mesh element dimension):
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ux, meaning the derivative of u with respect to x, defined when edim = sdim or edim=0
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uxy, meaning a second derivative, defined when edim = sdim
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uTx, the tangential derivative variable, meaning the x-component of the tangential projection of the gradient, defined when 0 < edim < sdim
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uTxy, meaning xy-component of the tangential projection of the second derivative, defined when edim < sdim
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Specify bubble shape functions in the model.shape field of the model object. The constructor of a bubble shape function is
shbub. The following properties are allowed:
The bubble element defines the following field variables. Denote basename with
u, and let
x and
y denote (not necessarily distinct) spatial coordinates. The variables are (
sdim = space dimension and
edim = mesh element dimension):
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u, defined when edim ≤ mdim, u = 0 if edim < mdim.
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ux, meaning the derivative of u with respect to x, defined when edim = mdim = sdim.
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uTx, the tangential derivative variable, meaning the x-component of the tangential projection of the gradient, defined when mdim < sdim and edim ≤ mdim. uTx = 0 if edim < mdim.
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uTxy, meaning the xy-component of the tangential projection of the second derivative, defined when mdim < sdim and edim ≤ mdim. uTxy = 0 if edim < mdim.
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Specify curl shape functions in the model.shape field of the model object. The constructor of the curl shape function is
shcurl. The following properties are allowed:
The default for compnames is
fieldname concatenated with the spatial coordinate names. The default for
dofbasename is
tallcomponents, where
allcomponents is the concatenation of the names in
compnames.
The property dcompnames lists the names of the component of the antisymmetric matrix
where Ai are the vector field components and
xi are the spatial coordinates. The components are listed in row order. If a name is the empty string, the field variable corresponding to that component is not defined. If you have provided
compnames, the default for the entries in
dcompnames is
compnames(j) sdimnames(i) compnames(i) sdimnames(j) for off-diagonal elements. If only
fieldname has been given, the default for the entries are
dfieldname sdimnames(i)sdimnames(j). Diagonal elements are not defined per defaults. For example,
shcurl('order',3,'fieldname','A','dcompnames', {'','','curlAy','curlAz','','','','curlAx',''}).
The curl element defines the following degrees of freedom: dofbasename d c, where
d = 1 for DOFs in the interior of an edge,
d = 2 for DOFs in the interior of a surface, and so forth, and
c is a number between 0 and
d − 1.
The curl element defines the following field variables (where comp is a component name from
compnames, and
dcomp is a component from
dcompnames,
sdim = space dimension and
edim = mesh element dimension):
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comp, meaning a component of the vector, defined when edim = sdim.
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tcomp, meaning one component of the tangential projection of the vector onto the mesh element, defined when edim < sdim.
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compx, meaning the derivative of a component of the vector with respect to global spatial coordinate x, defined when edim = sdim.
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tcompTx, the tangential derivative variable, meaning the x component of the projection of the gradient of tcomp onto the mesh element, defined when edim < sdim. Here, x is the name of a spatial coordinate.
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dcomp, meaning a component of the anti-symmetrized gradient, defined when edim = sdim.
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tdcomp, meaning one component of the tangential projection of the anti-symmetrized gradient onto the mesh element, defined when edim < sdim.
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For performance reasons, use dcomp in expressions involving the curl rather than writing it as the difference of two gradient components.
Specify discontinuous Lagrange shape functions in the model.shape field of the model object. The constructor of the discontinuous Lagrange shape functions is either
shdisc, for discontinuous Lagrange shape functions, or
shhwdisc, for nodal discontinuous Lagrange shape functions. The difference between these two is that the latter has optimal placement of degrees of freedom on triangular and tetrahedral meshes with respect to certain interpolation error estimates, whereas the former is available on all types of mesh elements with arbitrary polynomial order
k. However, the available numerical integration formulas usually limits the usefulness to
k ≤ 5 (
k ≤ 4 for tetrahedral meshes). The following properties are allowed:
The shhwdisc (nodal discontinuous Lagrange) shape function has the same properties as the
shdisc (nodal discontinuous Lagrange) shape function, except that the mesh element dimension
mdim cannot be set; it is instead assumed equal to
sdim. That is,
shhwdisc shape functions are only usable on the top dimension of the geometry.
The discontinuous element defines the following field variables. Denote basename with
u, and let
x denote the spatial coordinates. The variables are (
edim is the mesh element dimension):
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u, defined when edim = mdim.
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ux, meaning the derivative of u with respect to x, defined when edim = mdim = sdim.
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uTx, the tangential derivative variable, meaning the derivative of u with respect to x, defined when edim = mdim < sdim.
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Specify density shape functions in the model.shape field of the model object. The constructor of the density shape function is
shdens. The following properties are allowed:
The density element defines the following field variables. Denote basename with
u, and let
x denote the spatial coordinates. The variables are (
edim is the mesh element dimension):
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u, defined when edim = sdim.
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ux, meaning the derivative of u with respect to x, defined when edim = sdim.
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Specify Gauss point data shape functions in the model.shape field of the model object. The constructor of the density shape function is
shgp. The following properties are allowed:
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Value type in case of using split representation of complex variables 1
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u, defined when edim <= mdim.
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Specify divergence shape functions in the model.shape field of the model object. The constructor of the divergence shape function is
shdiv. The following properties are allowed:
The default for compnames is
fieldname concatenated with the spatial coordinate names. The default for
dofbasename is
nallcomponents, where
allcomponents is the concatenation of the names in
compnames.
The vector element defines the following degrees of freedom: dofbasename on element boundaries, and
dofbasename sdim c,
c =
0, …,
sdim − 1 for DOFs in the interior.
The divergence element defines the following field variables (where comp is a component name from
compnames,
divname is the
divname,
sdim = space dimension and
edim = mesh element dimension):
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comp, meaning a component of the vector, defined when edim = sdim.
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ncomp, meaning one component of the projection of the vector onto the normal of mesh element, defined when edim = sdim – 1.
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compx, meaning the derivative of a component of the vector with respect to global spatial coordinate x, defined when edim = sdim.
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ncompTx, the tangential derivative variable, meaning the x component of the projection of the gradient of ncomp onto the mesh element, defined when edim < sdim. Here, x is the name of a spatial coordinate. ncompTx = 0.
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divname, means the divergence of the vector field.
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For performance reasons, prefer using divname in expressions involving the divergence rather than writing it as the sum of
sdim gradient components.