Python tensor.sqr函数代码示例

def get_mean_square_norm_gradients_variance_method_00(D_by_layer, cost, accum = 0):

    # This returns a theano variable that will be of shape (minibatch_size, ).
    # It will contain, for each training example, the associated mean of the
    # variance wrt the gradient of that minibatch.

    for (layer_name, D) in D_by_layer.items():

        input = D['input']
        input_square_norms = tensor.sqr(D['input']).sum(axis=1)
        backprop_output = tensor.grad(cost, D['output'])
        # I don't think that theano recomputes this.
        # It should be just redundant nodes in the computational graph
        # that end up being computed only once anyways.
        grad_weight = tensor.grad(cost, D['weight'])
        grad_bias = tensor.grad(cost, D['bias'])
        backprop_output_square_norms = tensor.sqr(backprop_output).sum(axis=1)

        if D.has_key('weight'):
            A = input_square_norms * backprop_output_square_norms
            C = tensor.sqr(grad_weight).sum() # all the terms get this "middle" expression added to them
            B = (backprop_output.dot(grad_weight.T) * input).sum(axis=1)

            accum += (A - 2*B + C)

        if D.has_key('bias'):
            # this last `sum` could be a component-wise `max` if we wanted
            # to carry the maximum of the variances instead of the sum of squares
            accum = accum + tensor.sqr(backprop_output - grad_bias.reshape((1,-1))).sum(axis=1)


    return accum

def batchnorm(X, rescale=None, reshift=None, u=None, s=None, e=1e-8):
    """
    batchnorm with support for not using scale and shift parameters
    as well as inference values (u and s) and partial batchnorm (via a)
    will detect and use convolutional or fully connected version
    """
    g = rescale
    b = reshift
    if X.ndim == 4:
        if u is not None and s is not None:
            # use normalization params given a priori
            b_u = u.dimshuffle('x', 0, 'x', 'x')
            b_s = s.dimshuffle('x', 0, 'x', 'x')
        else:
            # compute normalization params from input
            b_u = T.mean(X, axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
            b_s = T.mean(T.sqr(X - b_u), axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
        # batch normalize
        X = (X - b_u) / T.sqrt(b_s + e)
        if g is not None and b is not None:
            # apply rescale and reshift
            X = X*T.exp(0.2*g.dimshuffle('x', 0, 'x', 'x')) + b.dimshuffle('x', 0, 'x', 'x')
    elif X.ndim == 2:
        if u is None and s is None:
            # compute normalization params from input
            u = T.mean(X, axis=0)
            s = T.mean(T.sqr(X - u), axis=0)
        # batch normalize
        X = (X - u) / T.sqrt(s + e)
        if g is not None and b is not None:
            # apply rescale and reshift
            X = X*T.exp(0.2*g) + b
    else:
        raise NotImplementedError
    return X

def sgd_updates_adadelta(params,cost,rho=0.95,epsilon=1e-6,norm_lim=9,word_vec_name='Words'):
    """
    adadelta update rule, mostly from
    https://groups.google.com/forum/#!topic/pylearn-dev/3QbKtCumAW4 (for Adadelta)
    """
    updates = OrderedDict({})
    exp_sqr_grads = OrderedDict({})
    exp_sqr_ups = OrderedDict({})
    gparams = []
    for param in params:
        empty = numpy.zeros_like(param.get_value())
        exp_sqr_grads[param] = theano.shared(value=as_floatX(empty),name="exp_grad_%s" % param.name)
        gp = T.grad(cost, param)
        exp_sqr_ups[param] = theano.shared(value=as_floatX(empty), name="exp_grad_%s" % param.name)
        gparams.append(gp)
    for param, gp in zip(params, gparams):
        exp_sg = exp_sqr_grads[param]
        exp_su = exp_sqr_ups[param]
        up_exp_sg = rho * exp_sg + (1 - rho) * T.sqr(gp)
        updates[exp_sg] = up_exp_sg
        step =  -(T.sqrt(exp_su + epsilon) / T.sqrt(up_exp_sg + epsilon)) * gp
        updates[exp_su] = rho * exp_su + (1 - rho) * T.sqr(step)
        stepped_param = param + step
        if (param.get_value(borrow=True).ndim == 2) and (param.name!='Words'):
            col_norms = T.sqrt(T.sum(T.sqr(stepped_param), axis=0))
            desired_norms = T.clip(col_norms, 0, T.sqrt(norm_lim))
            scale = desired_norms / (1e-7 + col_norms)
            tmp=stepped_param * scale
            tmp=T.cast(tmp,'float32')
            #print param.type,tmp.type
            updates[param] = tmp
        else:
            updates[param] = stepped_param
            #print param.type,stepped_param.type
    return updates 

 def applyConstraint(self, param):
     if param.ndim != 4 and param.ndim != 2:
         warnings.warn("Norm constraints are normally applied to matrices"
                       +" or 4-dimensional tensors, but currently got "
                       +"%d dimensions, please make sure this is the desired"
                       +" parameter to apply norm constraints" % param.ndim)
         
     needFlip = False
     if param.ndim == 4: # a hack for conv layer filters
         prevShape = param.shape
         # conv layer filter shape is (nChannelOut, nChannelIn, r, c)
         param = param.flatten(2)
         # now it is (nout, nin), which is different from (nin, nout) 
         # from fulling connected networks, so need to flip here
         needFlip = True
     
     if needFlip:
         col_norm = T.sqrt(T.sum(T.sqr(param), axis=1, keepdims=True))
     else:
         col_norm = T.sqrt(T.sum(T.sqr(param), axis=0, keepdims=True))
         
     param /= (col_norm+1e-7)
     param *= self.norm
     
     if needFlip:
         param = param.reshape(prevShape)
                     
     return param

def sgd_updates_adadelta(params, cost, rho=0.95, epsilon=1e-6,
        norm_lim=9, word_vec_name='embedding'):
    updates = OrderedDict({})
    exp_sqr_grads = OrderedDict({})
    exp_sqr_ups = OrderedDict({})
    gparams = [] 
    for param in params:
        empty = np.zeros_like(param.get_value())
        exp_sqr_grads[param] = theano.shared(value=as_floatX(empty),name="exp_grad_%s" % param.name)
        gp = T.grad(cost, param)
        exp_sqr_ups[param] = theano.shared(value=as_floatX(empty), name="exp_grad_%s" % param.name)
        gparams.append(gp)

    for param, gp in zip(params, gparams):
        exp_sg = exp_sqr_grads[param] 
        exp_su = exp_sqr_ups[param]
        up_exp_sg = rho * exp_sg + (1 - rho) * T.sqr(gp)
        updates[exp_sg] = up_exp_sg
        step =  -(T.sqrt(exp_su + epsilon) / T.sqrt(up_exp_sg + epsilon)) * gp
        updates[exp_su] = rho * exp_su + (1 - rho) * T.sqr(step)
        stepped_param = param + step
        
        if (param.get_value(borrow=True).ndim == 2) and (param.name!='embedding'):
            col_norms = T.sqrt(T.sum(T.sqr(stepped_param), axis=0)) 
            desired_norms = T.clip(col_norms, 0, T.sqrt(norm_lim)) 
            scale = desired_norms / (1e-7 + col_norms)
            updates[param] = stepped_param * scale
        else:
            updates[param] = stepped_param
    return updates

def build_cost_functional_L2norm_w_reg(lambda_val,h,y_sym,Thetas):
	""" 
	build_cost_functional_L2norm (with regularization) J=J_y(Theta,b) # J\equiv J_y(\Theta,b), 
	for the L2 norm, or Euclidean space norm, but now with 
	regularization

	INPUT/PARAMETERS
	================
	@type y_sym  : theano symbolic matrix, such as T.matrix() or theano shared variable
	@param y_sym : output data as a symbolic theano variable or theano shared variable
NOTE: y_sym = T.matrix(); # this could be a vector, but I can keep y to be "general" in size dimensions
	
	@type h     : theano shared variable of size dims. (K,m) (size dim. might be (m,K) due to right action
	@param h    : hypothesis

	@type Thetas : tuple, list, or (ordered) iterable of Theta's as theano shared variables, of length L
	@params Thetas : weights or parameters thetas for all the layers l=1,2,...L-1
	NOTE: remember, we want a list of theano MATRICES, themselves, not the class

	RETURN/OUTPUTS
	==============
	@type J_theta : theano symbolic expression (computational graph)

	"""
	J_theta = np.cast[theano.config.floatX](0.5) * T.mean(T.sqr(h-y_sym))

	# T.sqr is element-wise operation (take the square of each element), and so it's an automorphism
	reg_term = T.mean( [ T.sum( T.sqr(Theta), acc_dtype=theano.config.floatX) for Theta in Thetas], acc_dtype=theano.config.floatX )
	reg_term = np.cast[theano.config.floatX](lambda_val/ (2.))*reg_term

	J_theta = J_theta + reg_term
	return J_theta

def AdadeltaUpdate(params,cost,stepSize=1.0,rho=0.95,epsilon=1e-6,norm_lim=9):
    updates=OrderedDict({})
    exp_sqr_grads=OrderedDict({})
    exp_sqr_update=OrderedDict({})
    g_params=[]
    for param in params:
        empty=np.zeros_like(param.get_value())
        exp_sqr_grads[param]=theano.shared(value=as_floatX(empty),name='exp_grad_%s'%param.name)
        exp_sqr_update[param]=theano.shared(value=as_floatX(empty),name='exp_grad_%s'%param.name)
        gp=T.grad(cost,param)
        g_params.append(gp)
    for param,gp in zip(params,g_params):
        exp_sg=exp_sqr_grads[param]
        exp_su=exp_sqr_update[param]
        update_exp_sg=rho*exp_sg+(1-rho)*T.sqr(gp)#????
        updates[exp_sg]=update_exp_sg
        
        step=-(T.sqrt(exp_su+epsilon)/T.sqrt(update_exp_sg+epsilon))*gp
        stepped_param=param+step*stepSize
        
        update_exp_su=rho*exp_su+(1-rho)*T.sqr(step)
        updates[exp_su]=update_exp_su

        if param.get_value(borrow=True).ndim==2 and param.name!='wordVec':
            col_norms=T.sqrt(T.sum(T.sqr(stepped_param),axis=0))
            desired_norms=T.clip(col_norms,0,T.sqrt(norm_lim))#???
            scale=desired_norms/(1e-7+col_norms)
            updates[param]=stepped_param*scale
        else:
            updates[param]=stepped_param
    return updates

  def get_layer_monitoring_channels(self,state_below=None,state=None,target=None):
    rval=OrderedDict()
    W,=self.transformer.get_params()
    rval['norm']=T.sqrt(T.sqr(W).sum())
    if(target is not None) and ((state_below is not None) or (state is not None)):
        if state is None:
            state=self.fprop(state_below)
        target=1.-target  #0/1 dissim/sim to 1/0 distances
        rmse=T.sqrt(T.mean(T.sqr(state-target)))
        rval['rmse']=rmse.mean()
        if self.costfn=='margin':
            thresh=self.costparam
        elif self.costfn=='cauchy':
            thresh=2./(1.+T.exp(self.costparam))
        else:
            thresh=0.5
        yhat=state<thresh
        y=target<0.5
        wrong_bit=T.cast(T.neq(y,yhat),state.dtype)
        rval['01_loss']=wrong_bit.mean()

        y=T.cast(y,state.dtype)
        yhat=T.cast(yhat,state.dtype)
        tp=(y*yhat).sum()
        fp=((1-y)*yhat).sum()
        prec=compute_precision(tp,fp)
        rec=compute_recall(y,tp)
        f1=compute_f1(prec,rec)
        rval['neg_precision']=-prec
        rval['neg_recall']=-rec
        rval['neg_f1']=-f1
        return rval

def cosine_similarity(y_true, y_pred):
    norm_y_true = T.sqrt(T.sum(T.sqr(y_true), 1, keepdims=True))
    norm_y_pred = T.sqrt(T.sum(T.sqr(y_pred), 1, keepdims=True))
    dot = T.tensordot(y_true, y_pred, axes=[1,1])
    cossim = dot / (norm_y_true * norm_y_pred)
    objective = 1-cossim
    return objective.mean(axis=-1)

    def get_updates(self, grads):
        grads = OrderedDict(grads)
        updates = OrderedDict()

        for param in grads.keys():
            # mean_squared_grad := E[g^2]_{t-1}
            mean_square_grad = theano.shared(theano._asarray(
                param.get_value() * 0., dtype=theano.config.floatX), name='mean_square_grad_' + param.name, borrow=False)
            self.parameters.append(mean_square_grad)
            # mean_square_dx := E[(\Delta x)^2]_{t-1}
            mean_square_dx = theano.shared(theano._asarray(
                param.get_value() * 0., dtype=theano.config.floatX), name='mean_square_dx_' + param.name, borrow=False)
            self.parameters.append(mean_square_dx)

            # Accumulate gradient
            new_mean_squared_grad = self.decay * mean_square_grad + \
                (1 - self.decay) * T.sqr(grads[param])

            # Compute update
            rms_dx_tm1 = T.sqrt(mean_square_dx + self.epsilon)
            rms_grad_t = T.sqrt(new_mean_squared_grad + self.epsilon)
            delta_x_t = - rms_dx_tm1 / rms_grad_t * grads[param]

            # Accumulate updates
            new_mean_square_dx = self.decay * mean_square_dx + (1 - self.decay) * T.sqr(delta_x_t)

            # Apply update
            updates[mean_square_grad] = new_mean_squared_grad
            updates[mean_square_dx] = new_mean_square_dx
            updates[param] = param + delta_x_t

        return updates

def entropy_exp(X, g=None, b=None, u=None, s=None, a=1., e=1e-8):
    if X.ndim == 4:
        if u is not None and s is not None:
            b_u = u.dimshuffle('x', 0, 'x', 'x')
            b_s = s.dimshuffle('x', 0, 'x', 'x')
        else:
            b_u = T.mean(X, axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
            b_s = T.mean(T.sqr(X - b_u), axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
        if a != 1:
            b_u = (1. - a)*0. + a*b_u
            b_s = (1. - a)*1. + a*b_s
        X = (X - b_u) / T.sqrt(b_s + e)
        if g is not None and b is not None:
            X = X*T.exp(g.dimshuffle('x', 0, 'x', 'x'))+b.dimshuffle('x', 0, 'x', 'x')
    elif X.ndim == 2:
        if u is None and s is None:
            u = T.mean(X, axis=0)
            s = T.mean(T.sqr(X - u), axis=0)
        if a != 1:
            u = (1. - a)*0. + a*u
            s = (1. - a)*1. + a*s
        X = (X - u) / T.sqrt(s + e)
        if g is not None and b is not None:
            X = X*T.exp(g)+b
    else:
        raise NotImplementedError
    return X

def create_adam_updates(updates, params, gparams, gsums, xsums, lr, eps, beta1, beta2):
    i = theano.shared(np.float64(0.0).astype(theano.config.floatX))
    i_t = i + 1.0
    omb1_t = 1.0 - beta1**i_t
    omb2_t = 1.0 - beta2**i_t
    lr_t = lr * (T.sqrt(omb2_t) / omb1_t)
    for p, g, m, v in zip(params, gparams, gsums, xsums):
        if is_subtensor_op(p):
            origin, indexes = get_subtensor_op_inputs(p)
            m_sub = m[indexes]
            v_sub = v[indexes]
            m_t = beta1*m_sub + (1.0-beta1)*g
            v_t = beta2*v_sub + (1.0-beta2)*T.sqr(g)
            g_t = m_t / (T.sqrt(v_t) + eps)
            updates[m] = T.set_subtensor(m_sub, m_t)
            updates[v] = T.set_subtensor(v_sub, v_t)
            updates[origin] = T.inc_subtensor(p, -lr_t*g_t)
        else:
            m_t = beta1*m + (1.0-beta1)*g
            v_t = beta2*v + (1.0-beta2)*T.sqr(g)
            g_t = m_t / (T.sqrt(v_t) + eps)
            updates[m] = m_t
            updates[v] = v_t
            updates[p] = p - lr_t*g_t
    updates[i] = i_t

def batchnorm(X, g=None, b=None, u=None, s=None, a=1., e=1e-8):
    """
    batchnorm with support for not using scale and shift parameters
    as well as inference values (u and s) and partial batchnorm (via a)
    will detect and use convolutional or fully connected version
    """
    if X.ndim == 4:
        if u is not None and s is not None:
            b_u = u.dimshuffle('x', 0, 'x', 'x')
            b_s = s.dimshuffle('x', 0, 'x', 'x')
        else:
            b_u = tensor.mean(X, axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
            b_s = tensor.mean(tensor.sqr(X - b_u), axis=[0, 2, 3]).dimshuffle('x', 0, 'x', 'x')
        if a != 1:
            b_u = (1. - a)*0. + a*b_u
            b_s = (1. - a)*1. + a*b_s
        X = (X - b_u) / tensor.sqrt(b_s + e)
        if g is not None and b is not None:
            X = X*g.dimshuffle('x', 0, 'x', 'x') + b.dimshuffle('x', 0, 'x', 'x')
    elif X.ndim == 2:
        if u is None and s is None:
            u = tensor.mean(X, axis=0)
            s = tensor.mean(tensor.sqr(X - u), axis=0)
        if a != 1:
            u = (1. - a)*0. + a*u
            s = (1. - a)*1. + a*s
        X = (X - u) / tensor.sqrt(s + e)
        if g is not None and b is not None:
            X = X*g + b
    else:
        raise NotImplementedError
    return X

def mse(output, target, mean_over_second=True):
    """
    This is the Mean Square Error (MSE) across all dimensions, or per multibatch row (depending on mean_over_second).

    Parameters
    ----------
    output : tensor
        The symbolic tensor (or compatible) output from the network. (Comes from model).
    target : tensor
        The symbolic tensor (or compatible) target truth to compare the output against. (Comes from data).
    mean_over_second : bool
        Boolean whether or not to take the mean across all dimensions (True) or just the
        feature dimensions (False)

    Returns
    -------
    number
        The appropriate mean square error.
    """
    # The following definition came from the Conditional_nade project
    if mean_over_second:
        cost = T.mean(T.sqr(target - output))
    else:
        cost = T.mean(T.sqr(target - output).sum(axis=1))
    return cost

    def exe(self, mainloop):
        """
        .. todo::

            WRITEME
        """
        for k, p in mainloop.updates.items():
            for key in self.keys:
                if key in str(k):
                    token = 1

                    for waiver in self.waivers:
                        if waiver in str(k):
                            token = 0

                    if token:
                        updated_param = mainloop.updates[k]

                        if self.is_vector:
                            col_norms = T.sqrt(T.sqr(updated_param).sum(axis=0))
                            desired_norms = T.clip(col_norms, 0, self.weight_norm)
                            ratio = (desired_norms / (1e-7 + col_norms))
                            mainloop.updates[k] = updated_param * ratio
                        else:
                            norm = T.sqrt(T.sqr(updated_param).sum())
                            desired_norm = T.clip(norm, 0, self.weight_norm)
                            ratio = (desired_norm / (1e-7 + norm))
                            mainloop.updates[k] = updated_param * ratio