Re: Unclamped, one shot, pattern presentation

[kenkwok <kenkwok@cmu.edu>]

You need to write yr own code.  I modified CsUnitSpec::Compute_Net(Unit*
u) as follows:

void KcsUnitSpec::Compute_Net(Unit* u, int cycle) {
  KcsUnit* ku = (KcsUnit*)u;
  if(ku->lesioned) return;      // do not process if unit lesioned

  ClampType ct = clamp_type;
  if(clamp_type == HARD_THEN_SOFT_CLAMP) {
    if( cycle > n_hard) {
      ct = SOFT_CLAMP;
      }
    else {
      ct = HARD_CLAMP;
      }
  }

  if(ct == HARD_CLAMP) {
    if(ku->ext_flag & Unit::EXT) // no point in computing net for
clamped units!
      return;
    Compute_Net_impl(u);
  }
  else {   // soft clamping (or hard-then-soft), always compute net
    Compute_Net_impl(u);
    if(ct == SOFT_CLAMP)
      ku->net += clamp_gain * ku->ext;
  }
}

This defines a parameter n_hard which determines how many cycles the
pattern shd be clamped before releasing the clamping.


Mariano Bruno wrote:

>  Hi PDPers:I am trying to explore the hopfield model and its dinamic
> behavior.ONe of the problems I face for achive an oscillatory or
> chaotic regime is the next: I can't found anyway to un-clamp the input
> pattern. I mean, I would like to present only for an instant the
> pattern and then taking it out. In that way I could observe the
> dinamic evolution of the "isolated" network.Is there anyway for this
> kind of patter presentation, as a "one shot" in the PDP++?I will be
> very helpfull to anybody who could provide this info.Thanks