How to Update Input Files for Automated Differentiation (AD)
Components
There are no changes required in the [Components] block.
Materials
If you are using [Materials] block in your input file, refer to Table 1 and Table 2 for which material properties became AD and which stayed non-AD. If your object is using an AD material property, you will need to change its type according to Table 3 to make it work with AD.
Table 1: List of AD and non-AD material properties related to 1-phase flow
| Property name | AD? |
|---|---|
| D_h | NO |
| direction | NO |
| c | YES |
| cp | YES |
| cv | YES |
| e | YES |
| h | YES |
| H | YES |
| k | YES |
| Re | YES |
| rho | YES |
| rhoA | YES |
| rhouA | YES |
| rhoEA | YES |
| p | YES |
| Pr | YES |
| q_wall | YES |
| T | YES |
| T_wall | YES |
| v | YES |
| vel | YES |
Table 2: List of AD and non-AD material properties related to heat conduction
| Property name | AD? |
|---|---|
| density | YES |
| thermal_conductivity | YES |
| specific_heat | YES |
Table 3: Corresponding types of non-AD and AD materials.
| non-AD type | AD type |
|---|---|
| ConstantMaterial | ADConstantMaterial |
| GenericConstantMaterial | ADGenericConstantMaterial |
| ParsedMaterial | ADParsedMaterial |
| PrandtlNumberMaterial | ADPrandtlNumberMaterial |
| ReynoldsNumberMaterial | ADReynoldsNumberMaterial |
| WallHeatTransferCoefficient3EqnDittusBoelterMaterial | ADWallHeatTransferCoefficient3EqnDittusBoelterMaterial |
| WallFrictionChurchillMaterial | ADWallFrictionChurchillMaterial |
Postprocessors
If you are using [Postprocessors] block in your input file, use Table 4 to convert the types of postprocessors to AD.
Table 4: Corresponding types of non-AD and AD postprocessors.
| non-AD type | AD type |
|---|---|
| ElementIntegralMaterialProperty | ADElementIntegralMaterialProperty |
| ElementAverageMaterialProperty | ADElementAverageMaterialProperty |
| ElementExtremeMaterialProperty | ADElementExtremeMaterialProperty |
| FlowBoundaryFlux1Phase | ADFlowBoundaryFlux1Phase |
| FlowJunctionFlux1Phase | ADFlowJunctionFlux1Phase |
| HeatRateConvection1Phase | ADHeatRateConvection1Phase |
| HeatStructureEnergy | ADHeatStructureEnergy |
| HeatStructureEnergy3D | ADHeatStructureEnergy3D |
| HeatStructureEnergyRZ | ADHeatStructureEnergyRZ |
| SideFluxIntegralRZ | ADSideFluxIntegralRZ |
| SpecificImpulse1Phase | ADSpecificImpulse1Phase |
VectorPostprocessors
If you are using [VectorPostprocessors] block in your input file, use Table 5 to convert the types of vector postprocessors to AD.
Table 5: Corresponding types of non-AD and AD vector postprocessors.
| non-AD type | AD type |
|---|---|
| Sampler1DReal | ADSampler1DReal |
Time Integrators
Use Table 6 to convert time integrators. The changes are needed for explicit integration. Implicit integration does not need any changes, but it is listed for completeness. If type is given in the table, you will need to use the time integrator block in your input file like so:
[TimeIntegrator]
type = ...
other params
[]
Table 6: Time integrator conversion.
| Time integrator | How to update |
|---|---|
| implicit-euler | No change |
| bdf-2 | No change |
| explicit-euler | type = ActuallyExplicitEuler |
| explicit-tvd-rk-2 | type = ExplicitSSPRungeKutta, order = 2 |
| explicit-midpoint | type = ExplicitSSPRungeKutta, order = 2 |
Executioner
With your input file converted into AD, make sure that you set solve_type = NEWTON in the [Executioner] block.
Custom Closures
Custom closure are closure correlations specified on input file level. The following example shows how to update an input file using those:
Original input file
[Materials]
[f_wall_mat]
type = GenericConstantMaterial
block = 'pipe'
prop_names = 'f_D df_D/drhoA df_D/drhouA df_D/drhoEA'
prop_values = '0.123 0 0 0'
[]
[]
New input file
[Materials]
[f_wall_mat]
type = ADGenericConstantMaterial
block = 'pipe'
prop_names = 'f_D'
prop_values = '0.123'
[]
[]
Note that with AD, users no longer have to provide dX/dY properties.
Common errors related AD
If you see any of the following errors, it may indicate that the input file is running non-AD setup. If the above information does not help you to fix the problem, contact THM developers.
*** ERROR ***
The requested regular material property thermal_conductivity is declared as an AD property.
Either retrieve it as an AD property with getADMaterialProperty or declare it as a regular
property with declareProperty