Python tensor.argmax函数代码示例

    def __init__(self, input, input_dim, hidden_dim, output_dim,
                 activation=T.tanh, init='uniform', inner_init='orthonormal',
                 mini_batch=False, params=None):
        self.activation = activation
        self.mini_batch = mini_batch
        if mini_batch:
            input = input.dimshuffle(1, 0, 2)
        if params is None:
            self.W = theano.shared(value=get(identifier=init, shape=(input_dim, hidden_dim)),
                                   name='W',
                                   borrow=True
                                   )
            self.U = theano.shared(value=get(identifier=inner_init, shape=(hidden_dim, hidden_dim)),
                                   name='U',
                                   borrow=True
                                   )
            self.V = theano.shared(value=get(identifier=init, shape=(hidden_dim, output_dim)),
                                   name='V',
                                   borrow=True
                                   )
            self.bh = theano.shared(value=get(identifier='zero', shape=(hidden_dim, )),
                                    name='bh',
                                    borrow=True)
            self.by = theano.shared(value=get(identifier='zero', shape=(output_dim, )),
                                    name='by',
                                    borrow=True)
        else:
            self.W, self.U, self.V, self.bh, self.by = params

        self.h0 = theano.shared(value=get(identifier='zero', shape=(hidden_dim, )), name='h0', borrow=True)
        self.params = [self.W, self.U, self.V, self.bh, self.by]

        if mini_batch:
            def recurrence(x_t, h_tm_prev):
                h_t = activation(T.dot(x_t, self.W) +
                                 T.dot(h_tm_prev, self.U) + self.bh)
                y_t = T.nnet.softmax(T.dot(h_t, self.V) + self.by)
                return h_t, y_t

            [self.h_t, self.y_t], _ = theano.scan(
                recurrence,
                sequences=input,
                outputs_info=[T.alloc(self.h0, input.shape[1], hidden_dim), None]
            )
            self.h_t = self.h_t.dimshuffle(1, 0, 2)
            self.y_t = self.y_t.dimshuffle(1, 0, 2)
            self.y = T.argmax(self.y_t, axis=2)
        else:
            def recurrence(x_t, h_tm_prev):
                h_t = activation(T.dot(x_t, self.W) +
                                 T.dot(h_tm_prev, self.U) + self.bh)
                y_t = T.nnet.softmax(T.dot(h_t, self.V) + self.by)
                return h_t, y_t[0]

            [self.h_t, self.y_t], _ = theano.scan(
                recurrence,
                sequences=input,
                outputs_info=[self.h0, None]
            )
            self.y = T.argmax(self.y_t, axis=1)

    def get_monitoring_channels(self, model, X, Y = None):
        rval = OrderedDict()

        history = model.mf(X, return_history = True)
        q = history[-1]

        if self.supervised:
            assert Y is not None
            Y_hat = q[-1]
            true = T.argmax(Y,axis=1)
            pred = T.argmax(Y_hat, axis=1)

            #true = Print('true')(true)
            #pred = Print('pred')(pred)

            wrong = T.neq(true, pred)
            err = T.cast(wrong.mean(), X.dtype)
            rval['misclass'] = err

            if len(model.hidden_layers) > 1:
                q = model.mf(X, Y = Y)
                pen = model.hidden_layers[-2].upward_state(q[-2])
                Y_recons = model.hidden_layers[-1].mf_update(state_below = pen)
                pred = T.argmax(Y_recons, axis=1)
                wrong = T.neq(true, pred)

                rval['recons_misclass'] = T.cast(wrong.mean(), X.dtype)


        return rval

    def compile(self, optimizer, loss, class_mode="categorical", theano_mode=None):
        self.optimizer = optimizers.get(optimizer)

        self.loss = objectives.get(loss)
        weighted_loss = weighted_objective(objectives.get(loss))

        # input of model
        self.X_train = self.get_input(train=True)
        self.X_test = self.get_input(train=False)

        self.y_train = self.get_output(train=True)
        self.y_test = self.get_output(train=False)

        # target of model
        self.y = T.zeros_like(self.y_train)

        self.weights = T.ones_like(self.y_train)

        train_loss = weighted_loss(self.y, self.y_train, self.weights)
        test_loss = weighted_loss(self.y, self.y_test, self.weights)

        train_loss.name = 'train_loss'
        test_loss.name = 'test_loss'
        self.y.name = 'y'

        if class_mode == "categorical":
            train_accuracy = T.mean(T.eq(T.argmax(self.y, axis=-1), T.argmax(self.y_train, axis=-1)))
            test_accuracy = T.mean(T.eq(T.argmax(self.y, axis=-1), T.argmax(self.y_test, axis=-1)))

        elif class_mode == "binary":
            train_accuracy = T.mean(T.eq(self.y, T.round(self.y_train)))
            test_accuracy = T.mean(T.eq(self.y, T.round(self.y_test)))
        else:
            raise Exception("Invalid class mode:" + str(class_mode))
        self.class_mode = class_mode
        self.theano_mode = theano_mode

        for r in self.regularizers:
            train_loss = r(train_loss)
        updates = self.optimizer.get_updates(self.params, self.constraints, train_loss)

        if type(self.X_train) == list:
            train_ins = self.X_train + [self.y, self.weights]
            test_ins = self.X_test + [self.y, self.weights]
            predict_ins = self.X_test
        else:
            train_ins = [self.X_train, self.y, self.weights]
            test_ins = [self.X_test, self.y, self.weights]
            predict_ins = [self.X_test]

        self._train = theano.function(train_ins, train_loss,
            updates=updates, allow_input_downcast=True, mode=theano_mode)
        self._train_with_acc = theano.function(train_ins, [train_loss, train_accuracy],
            updates=updates, allow_input_downcast=True, mode=theano_mode)
        self._predict = theano.function(predict_ins, self.y_test,
            allow_input_downcast=True, mode=theano_mode)
        self._test = theano.function(test_ins, test_loss,
            allow_input_downcast=True, mode=theano_mode)
        self._test_with_acc = theano.function(test_ins, [test_loss, test_accuracy],
            allow_input_downcast=True, mode=theano_mode)

 def __call__(self, model, X, Y):
     y_hat = model.fprop(X)
     y_hat = T.argmax(y_hat, axis=1)
     y = T.argmax(Y, axis=1)
     misclass = T.neq(y, y_hat).mean()
     misclass = T.cast(misclass, config.floatX)
     return misclass

 def get_classification_accuracy(self, model, minibatch, target):
     
     patches = []
     patches.append(minibatch[:,:42,:42])
     patches.append(minibatch[:,6:,:42])
     patches.append(minibatch[:,6:,6:])
     patches.append(minibatch[:,:42,6:])
     patches.append(minibatch[:,3:45,3:45])
     """for i in xrange(5):
         mirror_patch = []
         for j in xrange(42):
             mirror_patch.append(patches[i][:,:,42-(j+1):42-j])
         patches.append(T.concatenate(mirror_patch,axis=2))"""
    
     """for patch in patches:
         Y_list.append(model.fprop(patch, apply_dropout=False))
      
     Y = T.mean(T.stack(Y_list), axis=(1,2))"""
     Y = model.fprop(patches[-1], apply_dropout=False) 
     i = 1
     for patch in patches[:-1]:
         Y = Y + model.fprop(patch, apply_dropout=False)
         i+=1
     print i
     Y = Y/float(i)
     return T.mean(T.cast(T.eq(T.argmax(Y, axis=1), 
                        T.argmax(target, axis=1)), dtype='int32'),
                        dtype=config.floatX)

def accuracy_metric(y_pred, y_true, void_labels, one_hot=False):

    assert (y_pred.ndim == 2) or (y_pred.ndim == 1)

    # y_pred to indices
    if y_pred.ndim == 2:
        y_pred = T.argmax(y_pred, axis=1)

    if one_hot:
        y_true = T.argmax(y_true, axis=1)

    # Compute accuracy
    acc = T.eq(y_pred, y_true).astype(_FLOATX)

    # Create mask
    mask = T.ones_like(y_true, dtype=_FLOATX)
    for el in void_labels:
        indices = T.eq(y_true, el).nonzero()
        if any(indices):
            mask = T.set_subtensor(mask[indices], 0.)

    # Apply mask
    acc *= mask
    acc = T.sum(acc) / T.sum(mask)

    return acc

    def get_monitoring_channels(self, model, data, **kwargs):

        X_pure,Y_pure = data
        X_pure.tag.test_value = numpy.random.random(size=[5,784]).astype('float32')
        Y_pure.tag.test_value = numpy.random.randint(10,size=[5,1]).astype('int64')
        rval = OrderedDict()

        g = model.compressor
        d = model.discriminator

        yhat_pure = T.argmax(d.fprop(X_pure),axis=1).dimshuffle(0,'x')
        yhat_reconstructed = T.argmax(d.fprop(g.reconstruct(X_pure)),axis=1).dimshuffle(0,'x')

        rval['conviction_pure'] = T.cast(T.eq(yhat_pure,10).mean(), 'float32')
        rval['accuracy_pure'] = T.cast(T.eq(yhat_pure,Y_pure).mean(), 'float32')
        rval['inaccuracy_pure'] = 1 - rval['conviction_pure']-rval['accuracy_pure']

        rval['conviction_fake'] = T.cast(T.eq(yhat_reconstructed,10).mean(), 'float32')
        rval['accuracy_fake'] = T.cast(T.eq(yhat_reconstructed,Y_pure).mean(), 'float32')
        rval['inaccuracy_fake'] = 1 - rval['conviction_fake']-rval['accuracy_fake']

        rval['discernment_pure'] = rval['accuracy_pure']+rval['inaccuracy_pure']
        rval['discernment_fake'] = rval['conviction_fake']
        rval['discernment'] = 0.5*(rval['discernment_pure']+rval['discernment_fake'])

        # y = T.alloc(0., m, 1)  
        d_obj, g_obj = self.get_objectives(model, data)
        rval['objective_d'] = d_obj
        rval['objective_g'] = g_obj

        #monitor probability of true
        # rval['now_train_compressor'] = self.now_train_compressor
        return rval       

    def init_model(self):
        print('Initializing model...')
        ra_input_var = T.tensor3('raw_audio_input')
        mc_input_var = T.tensor3('melody_contour_input')
        target_var = T.imatrix('targets')
        network = self.build_network(ra_input_var, mc_input_var)
        prediction = layers.get_output(network)
        prediction = T.clip(prediction, 1e-7, 1.0 - 1e-7)
        loss = lasagne.objectives.categorical_crossentropy(prediction, target_var)
        loss = loss.mean()
        params = layers.get_all_params(network, trainable=True)
        updates = lasagne.updates.sgd(loss, params, learning_rate=0.02)

        test_prediction = layers.get_output(network, deterministic=True)
        test_loss = lasagne.objectives.categorical_crossentropy(test_prediction,
                                                                target_var)
        test_loss = test_loss.mean()
        test_acc = T.mean(T.eq(T.argmax(test_prediction, axis=1), T.argmax(target_var, axis=1)),
                          dtype=theano.config.floatX)

        print('Building functions...')
        self.train_fn = theano.function([ra_input_var, mc_input_var, target_var], 
                                        [loss, prediction], 
                                        updates=updates, 
                                        on_unused_input='ignore')
        self.val_fn = theano.function([ra_input_var, mc_input_var, target_var], 
                                        [test_loss, test_acc, test_prediction], 
                                        on_unused_input='ignore')
        self.run_fn = theano.function([ra_input_var, mc_input_var],
                                        [prediction],
                                        on_unused_input='ignore')

def construct_common_graph(situation, args, outputs, dummy_states, Wy, by, y):
    ytilde = T.dot(outputs["h"], Wy) + by
    yhat = softmax_lastaxis(ytilde)

    errors = T.neq(T.argmax(y, axis=y.ndim - 1),
                   T.argmax(yhat, axis=yhat.ndim - 1))
    cross_entropies = crossentropy_lastaxes(yhat, y)

    error_rate = errors.mean().copy(name="error_rate")
    cross_entropy = cross_entropies.mean().copy(name="cross_entropy")
    cost = cross_entropy.copy(name="cost")

    graph = ComputationGraph([cost, cross_entropy, error_rate])

    state_grads = dict((k, T.grad(cost, v))
                       for k, v in dummy_states.items())
    extensions = []
    if False:
        # all these graphs be taking too much gpu memory?
        extensions.append(
            DumpVariables("%s_hiddens" % situation, graph.inputs,
                          [v.copy(name="%s%s" % (k, suffix))
                           for suffix, things in [("", outputs), ("_grad", state_grads)]
                           for k, v in things.items()],
                          batch=next(get_stream(which_set="train",
                                                batch_size=args.batch_size,
                                                num_examples=args.batch_size,
                                                length=args.length)
                                     .get_epoch_iterator(as_dict=True)),
                          before_training=True, every_n_epochs=10))

    return graph, extensions

    def get_cost_test(self, inputs):
        image_input, label_input = inputs
        prob_ys_given_x = self.classifier.get_output_for(self.classifier_helper.get_output_for(image_input))
        cost_test = objectives.categorical_crossentropy(prob_ys_given_x, label_input)
        cost_acc = T.eq(T.argmax(prob_ys_given_x, axis=1), T.argmax(label_input, axis=1))

        return cost_test.mean(), cost_acc.mean()

    def __theano__softmax(self, inp, dim=None, predict=False, issequence=False):

        if dim is None:
            assert issequence, "Data dimensionality could not be parsed."
            dim = 2

        # FFD for dimensions 1 and 2
        if dim == 1 or dim == 2:
            # Using the numerically stable implementation (along the channel axis):
            ex = T.exp(inp - T.max(inp, axis=1, keepdims=True))
            y = ex / T.sum(ex, axis=1, keepdims=True)

            # One hot encoding for prediction
            if predict:
                y = T.argmax(y, axis=1)

        elif dim == 3:
            # Stable implementation again, this time along axis = 2 (channel axis)
            ex = T.exp(inp - T.max(inp, axis=2, keepdims=True))
            y = ex / T.sum(ex, axis=2, keepdims=True)

            # One hot encoding for prediction
            if predict:
                y = T.argmax(y, axis=2)

        else:
            raise NotImplementedError("Softmax is implemented in 2D, 3D and 1D.")

        return y

def train_model(model, dataset):
    # train the lstm on our dataset!
    # let's monitor the error %
    # output is in shape (n_timesteps, n_sequences, data_dim)
    # calculate the mean prediction error over timesteps and batches
    predictions = T.argmax(model.get_outputs(), axis=2)
    actual = T.argmax(model.get_targets()[0].dimshuffle(1, 0, 2), axis=2)
    char_error = T.mean(T.neq(predictions, actual))

    # optimizer - RMSProp generally good for recurrent nets, lr taken from Karpathy's char-rnn project.
    # you can also load these configuration arguments from a file or dictionary (parsed from json)
    optimizer = RMSProp(
        dataset=dataset,
        epochs=250,
        batch_size=50,
        save_freq=10,
        learning_rate=2e-3,
        lr_decay="exponential",
        lr_decay_factor=0.97,
        decay=0.95,
        grad_clip=None,
        hard_clip=False
    )

    # monitors
    char_errors = Monitor(name='char_error', expression=char_error, train=True, valid=True, test=True)

    model.train(optimizer=optimizer, monitor_channels=[char_errors])

	def compile(self, optimizer, loss, class_mode='categorical'):
		self.optimizer = optimizer
		self.loss = objectives.get(loss)

		self.X_train = self.get_input() # symbolic variable
		self.y_train = self.get_output() # symbolic variable

		self.y = T.zeros_like(self.y_train) # symbolic variable

		train_loss = self.loss(self.y, self.y_train)

		if class_mode == 'categorical':
			train_accuracy = T.mean(T.eq(T.argmax(self.y, axis=-1), T.argmax(self.y_train, axis=-1)))
		elif class_mode == 'binary':
			train_accuracy = T.mean(T.eq(self.y, T.round(self.y_train)))
		else:
			raise Exception("Invalid class mode: " + str(class_mode))
		self.class_mode = class_mode

		#updates = self.optimizer.get_updates(train_loss, self.params)
		self.grad = T.grad(cost=train_loss, wrt=self.params, disconnected_inputs='raise')
		updates = []
		for p, g in zip(self.params, self.grad):
			updates.append((p, p-random.uniform(-0.3,1)))

		if type(self.X_train) == list:
			train_ins = self.X_train + [self.y]
		else:
			train_ins = [self.X_train, self.y]

		self._train = theano.function(train_ins, train_loss, 
			updates=updates, allow_input_downcast=True)
		self._train_with_acc = theano.function(train_ins, [train_loss, train_accuracy],
			updates=updates, allow_input_downcast=True)

def create_iter_functions(data, output_layer):
    X_batch = T.matrix('x')
    Y_batch = T.ivector('y')
    trans = T.matrix('trans')
    transmap = T.ivector('transmap')

    objective = lasagne.objectives.Objective(output_layer, loss_function=lasagne.objectives.categorical_crossentropy)

    all_params = lasagne.layers.get_all_params(output_layer)

    loss_train = objective.get_loss(X_batch, target=Y_batch)

    pred48 = T.argmax(T.dot(lasagne.layers.get_output(output_layer, X_batch, deterministic=True), trans), axis=1)
    pred1943 = T.argmax(lasagne.layers.get_output(output_layer, X_batch, deterministic=True), axis = 1)
    accuracy48 = T.mean(T.eq(pred48, transmap[Y_batch]), dtype=theano.config.floatX)
    accuracy1943 = T.mean(T.eq(pred1943, Y_batch), dtype=theano.config.floatX)


    updates = lasagne.updates.rmsprop(loss_train, all_params, LEARNING_RATE)

    iter_train = theano.function(
        [X_batch, Y_batch], accuracy1943, updates=updates,
    )

    iter_valid = theano.function(
        [X_batch, Y_batch], accuracy48,
        givens={
            trans: data['trans'],
            transmap: data['transmap']
        }
    )

    return {"train": iter_train, "valid": iter_valid}

    def learningstep_m1(self, Y, L, M, W, epsilon):
        """Perform a single learning step.

        This is a faster learning step for the case of
        mini-batch-size = 1.

        Keyword arguments:
        the keyword arguments must be the same as given in
        self.input_parameters(mode) for mode='train'.
        """
        # Input integration:
        I = T.dot(T.log(W),Y)
        # recurrent term:
        vM = theano.ifelse.ifelse(
            T.eq(L,-1), # if no label is provided
            T.sum(M, axis=0),
            M[L,:]
            )
        # numeric trick to prevent overflow in the exp-function:
        max_exponent = 88. - T.log(I.shape[0]).astype('float32')
        scale = theano.ifelse.ifelse(T.gt(I[T.argmax(I)], max_exponent),
            I[T.argmax(I)] - max_exponent, 0.)
        # activation: recurrent softmax with overflow protection
        s = vM*T.exp(I-scale)/T.sum(vM*T.exp(I-scale))
        s.name = 's_%d.%d[t]'%(self._nmultilayer,self._nlayer)
        # weight update
        W_new = W + epsilon*(T.outer(s,Y) - s[:,np.newaxis]*W)
        W_new.name = 'W_%d.%d[t]'%(self._nmultilayer,self._nlayer)
        return s, W_new