### 12.3 Session file configuration

#### 12.3.1 Solver Info

`EqType`

Specifies the PDE system to solve, based on the choices in the table above.
`Temperature`

Specifies the form of the thermal stresses to use. The choices
are:
`None`

: No stresses (default).
`Jacobian`

: Sets S_{t} = βJI, where β is a parameter defined in the parameters
section, J is the elemental Jacobian determinant and I is the identity matrix.
`Metric`

: A more complex term, based on the eigenvalues of the metric
tensor. This can only be used for simplex elements (triangles and tetrahedra).
Controlled again by the parameter β.

`BCType`

Specifies the type of boundary condition to apply when the `IterativeElasticSystem`

is being used.
`Normal`

: The boundary conditions are split into `NumSteps`

steps, as defined
by a parameter in the session file (default).
`Repeat`

: As the geometry is updated, re-evaluate the boundary conditions.
This enables, for example, a cirlce to be rotated continuously.

#### 12.3.2 Parameters

The following parameters can be specified in the `PARAMETERS`

section of the session file:

`nu`

: sets the Poisson ratio ν.

Default value: 0.25.
`E`

: sets the Young’s modulus E.

Default value: 1.
`beta`

: sets the thermal stress coefficient β.

Default value: 1.
`NumSteps`

: sets the number of steps to use in the case that the iterative elastic
system is enabled. Should be greater than 0.

Default value: 0.