Add a Standard Deviation node () by right-clicking a Definitions node in a Component and choosing it from the Physics Utilities submenu. It is also available on the Definitions ribbon toolbar, from the Physics Utilities menu. Use the Standard Deviation to add a variable equal to the deviation of the specified expression over the selection (domain, edge, boundary, or point). The variable can be accessed via its Name throughout the model.

Enter the Expression for which the standard deviation is to be computed.

The default Quadrature method is Gauss, which uses a pattern of integration points in the interior of mesh elements. Choose instead Gauss-Lobatto to use a different pattern including points at mesh element nodes. These predefined patterns are constructed so that a polynomial of at most the specified Integration order will be integrated exactly. If you have added custom Integration Rule nodes under Global Definitions, these are also available in the Quadrature method setting.

For the Gauss and Gauss-Lobatto quadrature methods, choose a suggested Integration order or User defined which will expose the Order expression field. The suggested even orders from 0 to 8 are available in all dimensions. The default is 4 which is appropriate for a second-order equation using quadratic shape functions. An order entered as a user-defined parameter expression must evaluate to an integer, but may be odd. The maximum order depends on the space dimension. It is 30 in 2D and 14 in 3D.

Choose a frame from the Integrate on frame list to set the volume element in the weak form integral. The default is Spatial..