Mercurial > pylearn
comparison pylearn/algorithms/mcRBM.py @ 1395:54b2268db0d7
mcRBM.contrastive_grad accepts optional "consider_constant" arg
| author | James Bergstra <bergstrj@iro.umontreal.ca> |
|---|---|
| date | Sat, 08 Jan 2011 17:14:44 -0500 |
| parents | 6402b3309ece |
| children | f82b80c841b2 |
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| 1394:48e8292e22e7 | 1395:54b2268db0d7 |
|---|---|
| 263 :math: \sum_i free_energy(pos_v[i]) - free_energy(neg_v[i]) | 263 :math: \sum_i free_energy(pos_v[i]) - free_energy(neg_v[i]) |
| 264 | 264 |
| 265 """ | 265 """ |
| 266 return (free_energy_fn(pos_v) - free_energy_fn(neg_v)).sum() | 266 return (free_energy_fn(pos_v) - free_energy_fn(neg_v)).sum() |
| 267 | 267 |
| 268 def contrastive_grad(free_energy_fn, pos_v, neg_v, wrt, other_cost=0): | 268 def contrastive_grad(free_energy_fn, pos_v, neg_v, wrt, other_cost=0, consider_constant=[]): |
| 269 """ | 269 """ |
| 270 :param free_energy_fn: lambda (TensorType matrix MxN) -> TensorType vector of M free energies | 270 :param free_energy_fn: lambda (TensorType matrix MxN) -> TensorType vector of M free energies |
| 271 :param pos_v: positive-phase sample of visible units | 271 :param pos_v: positive-phase sample of visible units |
| 272 :param neg_v: negative-phase sample of visible units | 272 :param neg_v: negative-phase sample of visible units |
| 273 :param wrt: TensorType variables with respect to which we want gradients (similar to the | 273 :param wrt: TensorType variables with respect to which we want gradients (similar to the |
| 297 cost=contrastive_cost(free_energy_fn, pos_v, neg_v) | 297 cost=contrastive_cost(free_energy_fn, pos_v, neg_v) |
| 298 if other_cost: | 298 if other_cost: |
| 299 cost = cost + other_cost | 299 cost = cost + other_cost |
| 300 return theano.tensor.grad(cost, | 300 return theano.tensor.grad(cost, |
| 301 wrt=wrt, | 301 wrt=wrt, |
| 302 consider_constant=[neg_v]) | 302 consider_constant=consider_constant+[neg_v]) |
| 303 | 303 |
| 304 ########################################### | 304 ########################################### |
| 305 # | 305 # |
| 306 # Expressions that are mcRBM-specific | 306 # Expressions that are mcRBM-specific |
| 307 # | 307 # |