Example #1
0
    def compute_grad(self,x,t):
        batch_size = nn.find_batch_size(x)
        # x = I[:,:,:,batch_size*l:batch_size*(l+1)]
        self.feedforward(x)

        wk,bk = self.weights[self.size-1]
        dwk,dbk = self.dweights[self.size-1]

        if ((self.size-1) in self.cfg.index_dense): delta_ = self.H[-1]-t
        else:                                       delta = self.H[-1]-t

        for k in range(1,self.size)[::-1]:
                    
            if k in self.cfg.index_dense:
                wk,bk = self.weights[k]
                dwk,dbk = self.dweights[k]
                dwk[:] = 1.0/batch_size*nn.dot(self.H_[k-1].T,delta_)
                dbk[:] = 1.0/batch_size*nn.sum(delta_,axis=0)
                
                delta_ = nn.dot(delta_, wk.T)
                if k-1 in self.cfg.index_pooling: 
                    delta  = delta_.T.reshape(self.cfg[k-1].shape[0], self.cfg[k-1].shape[1], self.cfg[k-1].shape[2], batch_size)
                elif (k-1 in self.cfg.index_convolution and k!=1):
                    delta  = delta_.T.reshape(self.cfg[k-1].shape[0], self.cfg[k-1].shape[1], self.cfg[k-1].shape[2], batch_size)
                    delta *= self.dH[k-1]
                elif (k-1 in self.cfg.index_dense and k!=1): delta_ *= self.dH[k-1]
                               
            elif k in self.cfg.index_pooling:
                delta  = self.cfg[k].applyPoolingUndo(self.H[k-1],delta,self.H[k])
                delta *= self.dH[k-1]
                        
            elif k in self.cfg.index_convolution:
                wk,bk = self.weights[k]
                dwk,dbk = self.dweights[k]    
                delta_ = delta.reshape(self.cfg[k].shape[0], self.cfg[k].shape[1] * self.cfg[k].shape[2] * batch_size).T
                dwk[:] = (1.0/batch_size)*self.cfg[k].applyConvOut(self.H[k-1], delta)
                dbk[:] = (1.0/batch_size)*nn.sum(delta_,axis=0)
                
                if k!=1: delta = self.cfg[k].applyConvDown(delta, wk) #convdown is unnecessary if k==1
                if (k-1 in self.cfg.index_convolution and k!=1): delta *= self.dH[k-1]
        
        #tied weights
        if self.cfg.want_tied:
            for hidden_pairs in self.cfg.tied_list: self.dweights.make_tied(*hidden_pairs)  
                
        for k in range(1,len(self.cfg)):
            if self.cfg[k].l2!=None:
                wk,bk   = self.weights[k]
                dwk,dbk = self.dweights[k]
                dwk    += self.cfg[k].l2*wk                
Example #2
0
 def compute_cost_euclidean(self,x,t):
     batch_size = nn.find_batch_size(x)
     # x = I[:,:,:,batch_size*l:batch_size*(l+1)]
     self.feedforward(x)
     return nn.sum(((1.0/batch_size)*(.5*(t-self.H[-1])**2)),axis=None)