Experimental layer - rough proposal

[tclose]

The more I have thought about splitting the user layer into a composition and parameterisation layer (see #41), and then adding an additional "state" layer as Alex proposed (see #36) the more I think it is a good idea.

One reason I have just come to is that it makes designing (what I reckon will be) a pretty comprehensive experimental layer fairly trivial. What I have in mind consists of:

• a duration
• a model (consisting of composition & abstraction layers)
• initial parameterisation and states (parameterisation & state layers)
• "updates" at arbitrary time points using full or partial parameterisation & state layer descriptions.
• "recording" (maybe using XPath-like syntax to select model elements)
• "playing" to input pre-recorded (or experimental) data.

Something like this

<?xml version="1.0"?>
<NineML>
  <Experiment name="test">
    <Duration unit="ms">2000</Duration>
    <Model>
      <Reference url="www.opensourcebrain.org/MyNetwork.xml">MyNetwork</Reference>
    </Model>
    <Initial>
      <Reference url="www.opensourcebrain.org/MyNetwork.xml">MyNetworkInitialState</Reference>
    </Initial>
    <Update>
      <AtTime units="ms">100</AtTime>
      <NetworkState>
        <PopulationState name="mossyFibres">
          <ComponentState name="poissonTrain">
            <InRegime name="spiking"/>
          </ComponentState>
        </PopulationState>
      </NetworkState>
    </Update>
    <Record name="granule_voltage">
      <Element>granule_cells/v</Element>
      <Indices>
        <ArrayValue>
          <ArrayValueRow index="10"/>
          <ArrayValueRow index="20"/>
          <ArrayValueRow index="30"/>
          <ArrayValueRow index="40"/>
          <ArrayValueRow index="50"/>
        </ArrayValue>
      </Indices>
    </Record>
    <Play>
      <ListeningPort>granule_cells/neuromodulator</ListeningPort>
      <DataSource>
        <ExternalArrayValue url="..."/>
      </DataSource>
    </Play>
  </Experiment>
  <Unit symbol="ms" dimension="time" power="0"/>
  <Dimension name="time" t="1"/>
</NineML>

Events and step changes could be implemented by updating the regime from idle to active.

I haven't looked at SEDML so I don't know how close this is to what they have but what do you think?

[tclose]

realised this is a duplicate of #22 so have copied it there