ConditionalDerivedVariables and DerivedVariables

[kperun]

There seems to be a problem with ConditionalDerivedVariables in combination with DerivedVariables, e.g.

<ConditionalDerivedVariable dimension="DIM_mV" name="V_bounded">
               <Case condition="(V_m.leq.V_peak)" value="(V_m)"/>
               <Case condition="(V_m.gt.V_peak)" value="(V_peak)"/>
</ConditionalDerivedVariable>
           
           
<DerivedVariable dimension="none" name="exp_arg" value="(V_bounded-V_th)/Delta_T"/> 

results in an error stating that V_bounded in exp_arg can not be found. However, if we use V_bounded in a state assignment, it seems to work.
Is this a bug or some kind of intended behavior in order to, e.g., avoid circular dependencies?

Regards,
Konstantin

[pgleeson]

@kperun This is a known issue, see #68.

One way around this might be to only use ConditionalDerivedVariables; instead of the DerivedVariable use a ConditionalDerivedVariable with a single Case statement with no condition (or a condition that's always true)

[pgleeson]

@kperun did you manage to work around that issue?

[borismarin]

@pgleeson ConditionalDerivedVariables with single Case statements (no condition) are converted to meaningless if-else blocks in backends like neuron-mod. Conditions that are always true are the correct workaround here.