Re: [Pcsim-users] Some clarifications

[Natschläger T. <Tho...@sc...>]

 
Hi Mathieu!

>
> Let's begin with AnalogInputNeuron::addAnalogValue(double v).
> Suppose that I call addAnalogValue(5). Will the output remain constant 
> until the next call to addAnalogValue or will it be equal to 5 for only 
> one simulation step?
>

AnalogInputNeuron simply holds a list of values and a current index into this list.
At reset() the index is set to 0 and Vm = values[index].
At each call to advance(), i.e. at each time-step, the index is incremented by one and Vm = values[index].
If index is to large Vm is "clamped" to its current value.
addAnalogValue(double v) does nothing more than adding v to the the end of the list of values.
Hence whether a call addAnalogValue(v) immediately influences Vm depends on the state
(i.e. on the value of index) of the input neuron.

>
> I would also like some help about SimNetwork::simulate(Time const & T) 
> (sounds crazy but I'm no longer sure of anything).
> If I call simulate(Time.ms(25)) will the simulation advance by 25 ms or 
> stop to 25 ms? More precisely, if I use simulate(Time.ms(25)) in a loop 
> will the simulation advance by 25 ms at each step or will it stick to 25 ms?

If you use simulate(Time.ms(25)) in a loop  the simulation advance by 25 ms at each step.
You need to call reset explicitly to set t=0ms.

>
> In fact I'm trying to use both PCSIM and webots 
> (http://www.cyberbotics.com/) for my experiment. Webots simulate the 
> robot and its environment and PCSIM is used to simulate the neural 
> network controlling the robot. Sensors values are injected from webots 
> to the network and the motor values are read from the network and sent 
> back to webots.
> I'm facing difficulties (the code runs but I have strange values on the 
> khepera sensors). Does anyone have some experience on this?
>

People at IGI (http://www.igi.tugraz.at/) are also using Webots but I do not know wether they use it in combination with PCSIM.
So maybe they can help you (at least a former college, Harald Burgsteiner, did something similar with CSIM - not PCSIM - and
real Khepera).

Regards

  -Thomas Natschläger