GenericKernelScalar
GenericKernelScalar acts as a switch between the AD/non-AD base class for objects that calculate residual vector contributions of volumetric (kernel) integrals on nonlinear scalar variables coupled with field variables.
This effectively allows a class to either inherit from KernelScalarBase for the non-AD or ADKernelScalarBase for the AD case via the boolean <is_ad>
.
See GenericKernel for a similar description for field variables.