Set pmech and efd in Genrou hard_coded_residual

[nkoukpaizan]

In the Genrou hard_coded_residual test, since we are not calling gen.initialize() and there are no control devices, pmech_set_ and efd_set_ are never initialized. They default to 0 in most situations I have tested, but this is not guaranteed. I've been experimenting with another way of handling those set points that led to an undefined behavior. Initializing those values to 0 where they are declared makes the test pass, but I doubt that's the behavior we want.

GridKit/tests/UnitTests/PhasorDynamics/GenrouTests.hpp

Line 163 in bcca730

// Allocate but not initialize generator model

Also see the discussion in #266 for the case where signal nodes are used.

cc @joshua-x-7 @abirchfield @pelesh

[pelesh]

We do need to test execution of the standalone residual function. My understanding is for that pmech_set_ and efd_set_ have to be initialized as they enter residual equations. Note we are not testing signal connections here, just residual equations.

This should be easy to fix imho.

[abirchfield]

This can be fixed by setting initial values to the efd_set_ and pmech_set_ variables of Genrou in the constructors. This will make the tests unambiguous. It should never affect normal usage because, except in testing, we will always call the initialization function before the residual is called. We can make this quick change.