def gen_model(idx, context, model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
                                   trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        if normalize:
            lengths = numpy.array([len(s) for s in sample])
            score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx]

    seq = _gencap(context)

    return (idx, seq)
Esempio n. 2
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def gen_model(idx, context, model, options, k, normalize, word_idict, sampling, params, tparams):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')


    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
                                   trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        if normalize:
            lengths = numpy.array([len(s) for s in sample])
            score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx]

    seq = _gencap(context)

    return (idx, seq)
    def _build(self):
        print 'Building model...'

        # build the sampling functions and model
        self.trng = RandomStreams(1234)
        use_noise = theano.shared(numpy.float32(0.), name='use_noise')

        params = capgen.init_params(self.options)
        params = capgen.load_params(self.model, params)
        self.tparams = capgen.init_tparams(params)

        # word index
        self.f_init, self.f_next = capgen.build_sampler(self.tparams, self.options, use_noise, self.trng)

        self.trng, use_noise, inps, \
        alphas, alphas_samples, cost, opt_outs = capgen.build_model(self.tparams, self.options)

        # get the alphas and selector value [called \beta in the paper]

        # create update rules for the stochastic attention
        hard_attn_updates = []
        if self.options['attn_type'] == 'stochastic':
            baseline_time = theano.shared(numpy.float32(0.), name='baseline_time')
            hard_attn_updates += [(baseline_time, baseline_time * 0.9 + 0.1 * opt_outs['masked_cost'].mean())]
            hard_attn_updates += opt_outs['attn_updates']
            
        self.f_alpha = theano.function(inps, alphas, name='f_alpha', updates=hard_attn_updates)
        if self.options['selector']:
            self.f_sels = theano.function(inps, opt_outs['selector'], name='f_sels', updates=hard_attn_updates)

        print 'Done'
Esempio n. 4
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def gen_model(model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)

    # DICTIONARY = "lexicon.txt"
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams,
                                   options,
                                   use_noise,
                                   trng,
                                   sampling=sampling)

    return (f_init, f_next, tparams, trng)
def gen_model(queue, rqueue, pid, model, options, k, normalize, word_idict,
              sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams,
                                   options,
                                   use_noise,
                                   trng,
                                   sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams,
                                   f_init,
                                   f_next,
                                   cc0,
                                   options,
                                   trng=trng,
                                   k=k,
                                   maxlen=200,
                                   stochastic=False)
        # adjust for length bias
        if normalize:
            lengths = numpy.array([len(s) for s in sample])
            score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx]

    while True:
        req = queue.get()
        # exit signal
        if req is None:
            break

        idx, context = req[0], req[1]

        print "Processing example %d in process # %d" % (idx, pid)
        seq = _gencap(context)
        print seq
        rqueue.put((idx, seq))
        print "Added example %d to the result queue" % idx

    print "gen_model process w/ pid %d has returned..." % pid
    return
Esempio n. 6
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def gen_model(queue, rqueue, pid, model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

	# tparams_list = []
    # f_init_list = []
    # f_next_list = []

    # for m in model:
    #     params = init_params(options)
    #     params = load_params(m, params)
    #     tparams_list.append( init_tparams(params) )
    #     f_init, f_next = build_sampler(tparams_list[-1], options, use_noise, trng, sampling=sampling)
    #     f_init_list.append( f_init )
    #     f_next_list.append( f_next )

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)


    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
                                   trng=trng, k=k, maxlen=200, stochastic=False)

        #sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
        #                           trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        #if normalize:
        lengths = numpy.array([len(s) for s in sample])
        score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx], score[sidx]

    while True:
        req = queue.get()
        # exit signal
        if req is None:
            break
        idx, context = req[0], req[1]
        print pid, '-', idx
        seq, score = _gencap(context)
        rqueue.put((idx, seq, score))

    return 
Esempio n. 7
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def load_model(model_path):
    # print 'loading model'
    model = model_path
    options = load_pkl(model + '.pkl')
    # build the sampling functions and model
    trng = RandomStreams(1234)
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')
    params = capgen.init_params(options)
    params = capgen.load_params(model, params)
    tparams = capgen.init_tparams(params)
    f_init, f_next = capgen.build_sampler(tparams, options, use_noise, trng)
    trng, use_noise, inps, alphas, alphas_samples, cost, opt_outs = capgen.build_model(tparams, options)
    # print 'done'
    return tparams, f_init, f_next, options, trng
Esempio n. 8
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def gen_model(model, options):

    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng)

    return f_init, f_next
Esempio n. 9
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def gen_model(model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)

    # DICTIONARY = "lexicon.txt"
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams,
                                   options,
                                   use_noise,
                                   trng,
                                   sampling=sampling)
    #trie = tr.TrieNode()
    #    #WordCount=0
    #    for word in open(DICTIONARY, "rt").read().split():
    #        word = string.lower(word)
    #
    #        WordCount += 1
    #        trie.insert( word )
    #
    #    print "Read %d words" % WordCount
    #
    #    def _gencap(cc0):
    #        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
    #                                   trng=trng, k=k, maxlen=200, stochastic=False,alpha=0.0)
    #        # adjust for length bias
    #        if normalize:
    #            lengths = numpy.array([len(s) for s in sample])
    #            score = score / lengths
    #        sidx = numpy.argsort(score)
    #        return [sample[i] for i in sidx]
    #    seq = _gencap(context)

    return (f_init, f_next, tparams, trng)
Esempio n. 10
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def gen_model(queue, rqueue, pid, model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
                                   trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        if normalize:
            lengths = numpy.array([len(s) for s in sample])
            score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx]

    while True:
        req = queue.get()
        # exit signal
        if req is None:
            break

        idx, context = req[0], req[1]

        print "Processing example %d in process # %d" % (idx, pid)
        seq = _gencap(context)
        print seq
        rqueue.put((idx, seq))
        print "Added example %d to the result queue" % idx

    print "gen_model process w/ pid %d has returned..." % pid
    return
Esempio n. 11
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def gen_model(queue, rqueue, pid, model, options, k, normalize, word_idict, sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams
    from capgen import build_sampler, gen_sample, load_params, init_params, init_tparams
    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    print 'For the first time'
    k2 = theano.shared(numpy.random.rand(10000, 100).astype('float32'))
    print 'its done'
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)
    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)
    print 'done finished now ...'
    def _gencap(cc0):
        sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
                                   trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        if normalize:
            lengths = numpy.array([len(s) for s in sample])
            score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx]
	print 'i \'m here now ....'
    while True:
        req = queue.get()
        # exit signal
        if req is None:
            break
        idx, context = req[0], req[1]
        context = context.astype(numpy.float32, copy=False)
        seq = _gencap(context)
        rqueue.put((idx, seq))
    print 'i am out now!'
    return 
Esempio n. 12
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def train(dim_word=100,  # word vector dimensionality
          ctx_dim=512,  # context vector dimensionality
          dim=1000,  # the number of LSTM units
          attn_type='stochastic',  # [see section 4 from paper]
          n_layers_att=1,  # number of layers used to compute the attention weights
          n_layers_out=1,  # number of layers used to compute logit
          n_layers_lstm=1,  # number of lstm layers
          n_layers_init=1,  # number of layers to initialize LSTM at time 0
          lstm_encoder=False,  # if True, run bidirectional LSTM on input units
          prev2out=False,  # Feed previous word into logit
          ctx2out=False,  # Feed attention weighted ctx into logit
          alpha_entropy_c=0.002,  # hard attn param
          RL_sumCost=True,  # hard attn param
          semi_sampling_p=0.5,  # hard attn param
          temperature=1.,  # hard attn param
          patience=10,
          max_epochs=5000,
          dispFreq=100,
          decay_c=0.,  # weight decay coeff
          alpha_c=0.,  # doubly stochastic coeff
          lrate=0.01,  # used only for SGD
          selector=False,  # selector (see paper)
          n_words=10000,  # vocab size
          maxlen=100,  # maximum length of the description
          optimizer='rmsprop',
          batch_size = 16,
          valid_batch_size = 16,
          saveto='model.npz',  # relative path of saved model file
          validFreq=1000,
          saveFreq=1000,  # save the parameters after every saveFreq updates
          sampleFreq=100,  # generate some samples after every sampleFreq updates
          data_path='./data',  # path to find data
          dataset='flickr8k',
          dictionary=None,  # word dictionary
          use_dropout=False,  # setting this true turns on dropout at various points
          use_dropout_lstm=False,  # dropout on lstm gates
          reload_=False,
          save_per_epoch=False): # this saves down the model every epoch

    # hyperparam dict
    model_options = locals().copy()
    model_options = validate_options(model_options)

    # reload options
    if reload_ and os.path.exists(saveto):
        print "Reloading options"
        with open('%s.pkl'%saveto, 'rb') as f:
            model_options = pkl.load(f)

    print "Using the following parameters:"
    print  model_options

    print 'Loading data'
    load_data, prepare_data = get_dataset(dataset)
    train, valid, test, worddict = load_data(path=data_path)
    if dataset == 'coco':
        valid, _ = valid # the second one contains all the validation data

    # index 0 and 1 always code for the end of sentence and unknown token
    word_idict = dict()
    for kk, vv in worddict.iteritems():
        word_idict[vv] = kk
    word_idict[0] = '<eos>'
    word_idict[1] = 'UNK'

    # Initialize (or reload) the parameters using 'model_options'
    # then build the Theano graph
    print 'Building model'
    params = init_params(model_options)
    if reload_ and os.path.exists(saveto):
        print "Reloading model"
        params = load_params(saveto, params)

    # numpy arrays -> theano shared variables
    tparams = init_tparams(params)

    # In order, we get:
    #   1) trng - theano random number generator
    #   2) use_noise - flag that turns on dropout
    #   3) inps - inputs for f_grad_shared
    #   4) cost - log likelihood for each sentence
    #   5) opts_out - optional outputs (e.g selector)
    trng, use_noise, \
          inps, alphas, alphas_sample,\
          cost, \
          opt_outs = \
          build_model(tparams, model_options)


    # To sample, we use beam search: 1) f_init is a function that initializes
    # the LSTM at time 0 [see top right of page 4], 2) f_next returns the distribution over
    # words and also the new "initial state/memory" see equation
    print 'Building sampler'
    f_init, f_next = build_sampler(tparams, model_options, use_noise, trng)

    # we want the cost without any the regularizers
    # define the log probability
    f_log_probs = theano.function(inps, -cost, profile=False,
                                        updates=opt_outs['attn_updates']
                                        if model_options['attn_type']=='stochastic'
                                        else None, allow_input_downcast=True)

    # Define the cost function + Regularization
    cost = cost.mean()
    # add L2 regularization costs
    if decay_c > 0.:
        decay_c = theano.shared(numpy.float32(decay_c), name='decay_c')
        weight_decay = 0.
        for kk, vv in tparams.iteritems():
            weight_decay += (vv ** 2).sum()
        weight_decay *= decay_c
        cost += weight_decay

    # Doubly stochastic regularization
    if alpha_c > 0.:
        alpha_c = theano.shared(numpy.float32(alpha_c), name='alpha_c')
        alpha_reg = alpha_c * ((1.-alphas.sum(0))**2).sum(0).mean()
        cost += alpha_reg

    hard_attn_updates = []
    # Backprop!
    if model_options['attn_type'] == 'deterministic':
        grads = tensor.grad(cost, wrt=itemlist(tparams))
    else:
        # shared variables for hard attention
        baseline_time = theano.shared(numpy.float32(0.), name='baseline_time')
        opt_outs['baseline_time'] = baseline_time
        alpha_entropy_c = theano.shared(numpy.float32(alpha_entropy_c), name='alpha_entropy_c')
        alpha_entropy_reg = alpha_entropy_c * (alphas*tensor.log(alphas)).mean()
        # [see Section 4.1: Stochastic "Hard" Attention for derivation of this learning rule]
        if model_options['RL_sumCost']:
            grads = tensor.grad(cost, wrt=itemlist(tparams),
                                disconnected_inputs='raise',
                                known_grads={alphas:(baseline_time-opt_outs['masked_cost'].mean(0))[None,:,None]/10.*
                                            (-alphas_sample/alphas) + alpha_entropy_c*(tensor.log(alphas) + 1)})
        else:
            grads = tensor.grad(cost, wrt=itemlist(tparams),
                            disconnected_inputs='raise',
                            known_grads={alphas:opt_outs['masked_cost'][:,:,None]/10.*
                            (alphas_sample/alphas) + alpha_entropy_c*(tensor.log(alphas) + 1)})
        # [equation on bottom left of page 5]
        hard_attn_updates += [(baseline_time, baseline_time * 0.9 + 0.1 * opt_outs['masked_cost'].mean())]
        # updates from scan
        hard_attn_updates += opt_outs['attn_updates']

    # to getthe cost after regularization or the gradients, use this
    # f_cost = theano.function([x, mask, ctx], cost, profile=False)
    # f_grad = theano.function([x, mask, ctx], grads, profile=False)

    # f_grad_shared computes the cost and updates adaptive learning rate variables
    # f_update updates the weights of the model
    lr = tensor.scalar(name='lr')
    f_grad_shared, f_update = eval(optimizer)(lr, tparams, grads, inps, cost, hard_attn_updates)

    print 'Optimization'

    # [See note in section 4.3 of paper]
    train_iter = HomogeneousData(train, batch_size=batch_size, maxlen=maxlen)

    if valid:
        kf_valid = KFold(len(valid[0]), n_folds=len(valid[0])/valid_batch_size, shuffle=False)
    if test:
        kf_test = KFold(len(test[0]), n_folds=len(test[0])/valid_batch_size, shuffle=False)

    # history_errs is a bare-bones training log that holds the validation and test error
    history_errs = []
    # reload history
    if reload_ and os.path.exists(saveto):
        history_errs = numpy.load(saveto)['history_errs'].tolist()
    best_p = None
    bad_counter = 0

    if validFreq == -1:
        validFreq = len(train[0])/batch_size
    if saveFreq == -1:
        saveFreq = len(train[0])/batch_size
    if sampleFreq == -1:
        sampleFreq = len(train[0])/batch_size

    uidx = 0
    estop = False
    for eidx in xrange(max_epochs):
        n_samples = 0

        print 'Epoch ', eidx

        for caps in train_iter:
            n_samples += len(caps)
            uidx += 1
            # turn on dropout
            use_noise.set_value(1.)

            # preprocess the caption, recording the
            # time spent to help detect bottlenecks
            pd_start = time.time()
            x, mask, ctx = prepare_data(caps,
                                        train[1],
                                        worddict,
                                        maxlen=maxlen,
                                        n_words=n_words)
            pd_duration = time.time() - pd_start

            if x is None:
                print 'Minibatch with zero sample under length ', maxlen
                continue

            # get the cost for the minibatch, and update the weights
            ud_start = time.time()
            cost = f_grad_shared(x, mask, ctx)
            f_update(lrate)
            ud_duration = time.time() - ud_start # some monitoring for each mini-batch

            # Numerical stability check
            if numpy.isnan(cost) or numpy.isinf(cost):
                print 'NaN detected'
                return 1., 1., 1.

            if numpy.mod(uidx, dispFreq) == 0:
                print 'Epoch ', eidx, 'Update ', uidx, 'Cost ', cost, 'PD ', pd_duration, 'UD ', ud_duration

            # Checkpoint
            if numpy.mod(uidx, saveFreq) == 0:
                print 'Saving...',

                if best_p is not None:
                    params = copy.copy(best_p)
                else:
                    params = unzip(tparams)
                numpy.savez(saveto, history_errs=history_errs, **params)
                pkl.dump(model_options, open('%s.pkl'%saveto, 'wb'))
                print 'Done'

            # Print a generated sample as a sanity check
            if numpy.mod(uidx, sampleFreq) == 0:
                # turn off dropout first
                use_noise.set_value(0.)
                x_s = x
                mask_s = mask
                ctx_s = ctx
                # generate and decode the a subset of the current training batch
                for jj in xrange(numpy.minimum(10, len(caps))):
                    sample, score = gen_sample(tparams, f_init, f_next, ctx_s[jj], model_options,
                                               trng=trng, k=5, maxlen=30, stochastic=False)
                    # Decode the sample from encoding back to words
                    print 'Truth ',jj,': ',
                    for vv in x_s[:,jj]:
                        if vv == 0:
                            break
                        if vv in word_idict:
                            print word_idict[vv],
                        else:
                            print 'UNK',
                    print
                    for kk, ss in enumerate([sample[0]]):
                        print 'Sample (', kk,') ', jj, ': ',
                        for vv in ss:
                            if vv == 0:
                                break
                            if vv in word_idict:
                                print word_idict[vv],
                            else:
                                print 'UNK',
                    print

            # Log validation loss + checkpoint the model with the best validation log likelihood
            if numpy.mod(uidx, validFreq) == 0:
                use_noise.set_value(0.)
                train_err = 0
                valid_err = 0
                test_err = 0

                if valid:
                    valid_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, valid, kf_valid).mean()
                if test:
                    test_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, test, kf_test).mean()

                history_errs.append([valid_err, test_err])

                # the model with the best validation long likelihood is saved seperately with a different name
                if uidx == 0 or valid_err <= numpy.array(history_errs)[:,0].min():
                    best_p = unzip(tparams)
                    print 'Saving model with best validation ll'
                    params = copy.copy(best_p)
                    params = unzip(tparams)
                    numpy.savez(saveto+'_bestll', history_errs=history_errs, **params)
                    bad_counter = 0

                # abort training if perplexity has been increasing for too long
                if eidx > patience and len(history_errs) > patience and valid_err >= numpy.array(history_errs)[:-patience,0].min():
                    bad_counter += 1
                    if bad_counter > patience:
                        print 'Early Stop!'
                        estop = True
                        break

                print 'Train ', train_err, 'Valid ', valid_err, 'Test ', test_err

        print 'Seen %d samples' % n_samples

        if estop:
            break

        if save_per_epoch:
            numpy.savez(saveto + '_epoch_' + str(eidx + 1), history_errs=history_errs, **unzip(tparams))

    # use the best nll parameters for final checkpoint (if they exist)
    if best_p is not None:
        zipp(best_p, tparams)

    use_noise.set_value(0.)
    train_err = 0
    valid_err = 0
    test_err = 0
    if valid:
        valid_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, valid, kf_valid)
    if test:
        test_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, test, kf_test)

    print 'Train ', train_err, 'Valid ', valid_err, 'Test ', test_err

    params = copy.copy(best_p)
    numpy.savez(saveto, zipped_params=best_p, train_err=train_err,
                valid_err=valid_err, test_err=test_err, history_errs=history_errs,
                **params)

    return train_err, valid_err, test_err

# ## Creating the Theano Graph  

# In[42]:

# build the sampling functions and model
trng = RandomStreams(1234)
use_noise = theano.shared(numpy.float32(0.), name='use_noise')

params = capgen.init_params(options)
params = capgen.load_params(model, params)
tparams = capgen.init_tparams(params)

# word index
f_init, f_next = capgen.build_sampler(tparams, options, use_noise, trng)


# In[43]:

trng,use_noise,inps, alphas, alphas_samples,cost, opt_outs = capgen.build_model(tparams, options)


# In[44]:

# get the alphas and selector value [called \beta in the paper]

# create update rules for the stochastic attention
hard_attn_updates = []
if options['attn_type'] == 'stochastic':
    baseline_time = theano.shared(numpy.float32(0.), name='baseline_time')
Esempio n. 14
0
def main(model, saveto, k=1, normalize=False, zero_pad=False, datasets='dev,test', data_path='./', sampling=False, pkl_name=None):
    # load model model_options
    if pkl_name is None:
        pkl_name = model
    with open('%s.pkl'% pkl_name, 'rb') as f:
        options = pkl.load(f)

    # fetch data, skip ones we aren't using to save time
    load_data, prepare_data = get_dataset(options['dataset'])
    _, valid, test, worddict = load_data(load_train=False, load_dev=True if 'dev' in datasets else False,
                                             load_test=True if 'test' in datasets else False, path=data_path)

    # <eos> means end of sequence (aka periods), UNK means unknown
    word_idict = dict()
    for kk, vv in worddict.iteritems():
        word_idict[vv] = kk
    word_idict[0] = '<eos>'
    word_idict[1] = 'UNK'

    # build sampler
    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams, options, use_noise, trng, sampling=sampling)

    # index -> words
    def _seqs2words(cc):
        ww = []
        for w in cc:
            if w == 0:
                break
            ww.append(word_idict[w])
        return ' '.join(ww)

    # unsparsify, reshape, and queue
    def _send_job(context):
        cc = context.todense().reshape([14*14,512])
        if zero_pad:
            cc0 = numpy.zeros((cc.shape[0]+1, cc.shape[1])).astype('float32')
            cc0[:-1,:] = cc
        else:
            cc0 = cc
        return create_sample(tparams, f_init, f_next, cc0, options, trng, k, normalize)

    ds = datasets.strip().split(',')

    # send all the features for the various datasets
    for dd in ds:
        if dd == 'dev':
            bar = Bar('Development Set...', max=len(valid[1]))
            caps = []
            for i in range(len(valid[1])):
                sample = _send_job(valid[1][i])
                cap = _seqs2words(sample)
                caps.append(cap)
                with open(saveto+'_status.json', 'w') as f:
                    json.dump({'current': i, 'total': len(valid[1])}, f)
                bar.next()
            bar.finish()
            with open(saveto, 'w') as f:
                print >>f, '\n'.join(caps)
            print 'Done'
        if dd == 'test':
            print 'Test Set...',
            caps = []
            for i in range(len(test[1])):
                sample = _send_job(test[1][i])
                cap = _seqs2words(sample)
                caps.append(cap)
                with open(saveto+'_status.json', 'w') as f:
                    json.dump({'current': i, 'total': len(test[1])}, f)
                bar.next()
            bar.finish()
            with open(saveto, 'w') as f:
                print >>f, '\n'.join(caps)
            print 'Done'
Esempio n. 15
0
def train(dim_word=100,  # word vector dimensionality
          ctx_dim=512,  # context vector dimensionality
          dim=1000,  # the number of LSTM units
          attn_type='deterministic',  # [see section 4 from paper]
          n_layers_att=1,  # number of layers used to compute the attention weights
          n_layers_out=1,  # number of layers used to compute logit
          n_layers_lstm=1,  # number of lstm layers
          n_layers_init=1,  # number of layers to initialize LSTM at time 0
          lstm_encoder=False,  # if True, run bidirectional LSTM on input units
          prev2out=False,  # Feed previous word into logit
          ctx2out=False,  # Feed attention weighted ctx into logit
          alpha_entropy_c=0.002,  # hard attn param
          RL_sumCost=False,  # hard attn param
          semi_sampling_p=0.5,  # hard attn param
          temperature=1.,  # hard attn param
          patience=10,
          max_epochs=5000,
          dispFreq=100,
          decay_c=0.,  # weight decay coeff
          alpha_c=0.,  # doubly stochastic coeff
          lrate=0.01,  # used only for SGD
          selector=False,  # selector (see paper)
          n_words=10000,  # vocab size
          maxlen=100,  # maximum length of the description
          optimizer='rmsprop',
          batch_size = 16,
          valid_batch_size = 2,#change from 16
          saveto='model.npz',  # relative path of saved model file
          validFreq=1000,
          saveFreq=1000,  # save the parameters after every saveFreq updates
          sampleFreq=5,  # generate some samples after every sampleFreq updates
          data_path='./data',  # path to find data
          dataset='flickr30k',
          dictionary=None,  # word dictionary
          use_dropout=False,  # setting this true turns on dropout at various points
          use_dropout_lstm=False,  # dropout on lstm gates
          reload_=False,
          save_per_epoch=False): # this saves down the model every epoch

    # hyperparam dict
    model_options = locals().copy()
    model_options = validate_options(model_options)

    # reload options
    if reload_ and os.path.exists(saveto):
        print "Reloading options"
        with open('%s.pkl'%saveto, 'rb') as f:
            model_options = pkl.load(f)

    print "Using the following parameters:"
    print  model_options

    print 'Loading data'
    load_data, prepare_data = get_dataset(dataset)
    train, valid, test, worddict = load_data(path=data_path)

    # index 0 and 1 always code for the end of sentence and unknown token
    word_idict = dict()
    for kk, vv in worddict.iteritems():
        word_idict[vv] = kk
    word_idict[0] = '<eos>'
    word_idict[1] = 'UNK'

    # Initialize (or reload) the parameters using 'model_options'
    # then build the Theano graph
    print 'Building model'
    params = init_params(model_options)
    if reload_ and os.path.exists(saveto):
        print "Reloading model"
        params = load_params(saveto, params)

    # numpy arrays -> theano shared variables
    tparams = init_tparams(params)

    # In order, we get:
    #   1) trng - theano random number generator
    #   2) use_noise - flag that turns on dropout
    #   3) inps - inputs for f_grad_shared
    #   4) cost - log likelihood for each sentence
    #   5) opts_out - optional outputs (e.g selector)
    trng, use_noise, \
          inps, alphas, alphas_sample,\
          cost, \
          opt_outs = \
          build_model(tparams, model_options)


    # To sample, we use beam search: 1) f_init is a function that initializes
    # the LSTM at time 0 [see top right of page 4], 2) f_next returns the distribution over
    # words and also the new "initial state/memory" see equation
    print 'Building sampler'
    f_init, f_next = build_sampler(tparams, model_options, use_noise, trng)

    # we want the cost without any the regularizers
    # define the log probability
    f_log_probs = theano.function(inps, -cost, profile=False,
                                        updates=opt_outs['attn_updates']
                                        if model_options['attn_type']=='stochastic'
                                        else None, allow_input_downcast=True)

    # Define the cost function + Regularization
    cost = cost.mean()
    # add L2 regularization costs
    if decay_c > 0.:
        decay_c = theano.shared(numpy.float32(decay_c), name='decay_c')
        weight_decay = 0.
        for kk, vv in tparams.iteritems():
            weight_decay += (vv ** 2).sum()
        weight_decay *= decay_c
        cost += weight_decay

    # Doubly stochastic regularization
    if alpha_c > 0.:
        alpha_c = theano.shared(numpy.float32(alpha_c), name='alpha_c')
        alpha_reg = alpha_c * ((1.-alphas.sum(0))**2).sum(0).mean()
        cost += alpha_reg

    hard_attn_updates = []
    # Backprop!
    if model_options['attn_type'] == 'deterministic':
        grads = tensor.grad(cost, wrt=itemlist(tparams))
    else:
        # shared variables for hard attention
        baseline_time = theano.shared(numpy.float32(0.), name='baseline_time')
        opt_outs['baseline_time'] = baseline_time
        alpha_entropy_c = theano.shared(numpy.float32(alpha_entropy_c), name='alpha_entropy_c')
        alpha_entropy_reg = alpha_entropy_c * (alphas*tensor.log(alphas)).mean()
        # [see Section 4.1: Stochastic "Hard" Attention for derivation of this learning rule]
        if model_options['RL_sumCost']:
            grads = tensor.grad(cost, wrt=itemlist(tparams),
                                disconnected_inputs='raise',
                                known_grads={alphas:(baseline_time-opt_outs['masked_cost'].mean(0))[None,:,None]/10.*
                                            (-alphas_sample/alphas) + alpha_entropy_c*(tensor.log(alphas) + 1)})
        else:
            grads = tensor.grad(cost, wrt=itemlist(tparams),
                            disconnected_inputs='raise',
                            known_grads={alphas:opt_outs['masked_cost'][:,:,None]/10.*
                            (alphas_sample/alphas) + alpha_entropy_c*(tensor.log(alphas) + 1)})
        # [equation on bottom left of page 5]
        hard_attn_updates += [(baseline_time, baseline_time * 0.9 + 0.1 * opt_outs['masked_cost'].mean())]
        # updates from scan
        hard_attn_updates += opt_outs['attn_updates']

    # to getthe cost after regularization or the gradients, use this
    # f_cost = theano.function([x, mask, ctx], cost, profile=False)
    # f_grad = theano.function([x, mask, ctx], grads, profile=False)

    # f_grad_shared computes the cost and updates adaptive learning rate variables
    # f_update updates the weights of the model
    lr = tensor.scalar(name='lr')
    f_grad_shared, f_update = eval(optimizer)(lr, tparams, grads, inps, cost, hard_attn_updates)

    print 'Optimization'

    # [See note in section 4.3 of paper]
    train_iter = HomogeneousData(train, batch_size=batch_size, maxlen=maxlen)

    if valid:
        kf_valid = KFold(len(valid[0]), n_folds=len(valid[0])/valid_batch_size, shuffle=False)
    if test:
        kf_test = KFold(len(test[0]), n_folds=len(test[0])/valid_batch_size, shuffle=False)

    # history_errs is a bare-bones training log that holds the validation and test error
    history_errs = []
    # reload history
    if reload_ and os.path.exists(saveto):
        history_errs = numpy.load(saveto)['history_errs'].tolist()
    best_p = None
    bad_counter = 0

    if validFreq == -1:
        validFreq = len(train[0])/batch_size
    if saveFreq == -1:
        saveFreq = len(train[0])/batch_size
    if sampleFreq == -1:
        sampleFreq = len(train[0])/batch_size

    uidx = 0
    estop = False
    for eidx in xrange(max_epochs):
        n_samples = 0

        print 'Epoch ', eidx

        for caps in train_iter:
            n_samples += len(caps)
            uidx += 1
            # turn on dropout
            use_noise.set_value(1.)

            # preprocess the caption, recording the
            # time spent to help detect bottlenecks
            pd_start = time.time()
            x, mask, ctx = prepare_data(caps,
                                        train[1],
                                        worddict,
                                        maxlen=maxlen,
                                        n_words=n_words)
            pd_duration = time.time() - pd_start

            if x is None:
                print 'Minibatch with zero sample under length ', maxlen
                continue

            # get the cost for the minibatch, and update the weights
            ud_start = time.time()
            cost = f_grad_shared(x, mask, ctx)
            f_update(lrate)
            ud_duration = time.time() - ud_start # some monitoring for each mini-batch

            # Numerical stability check
            if numpy.isnan(cost) or numpy.isinf(cost):
                print 'NaN detected'
                return 1., 1., 1.

            if numpy.mod(uidx, dispFreq) == 0:
                print 'Epoch ', eidx, 'Update ', uidx, 'Cost ', cost, 'PD ', pd_duration, 'UD ', ud_duration

            # Checkpoint
            if numpy.mod(uidx, saveFreq) == 0:
                print 'Saving...',

                if best_p is not None:
                    params = copy.copy(best_p)
                else:
                    params = unzip(tparams)
                numpy.savez(saveto, history_errs=history_errs, **params)
                pkl.dump(model_options, open('%s.pkl'%saveto, 'wb'))
                print 'Done'

            # Print a generated sample as a sanity check
            if numpy.mod(uidx, sampleFreq) == 0:
                # turn off dropout first
                use_noise.set_value(0.)
                x_s = x
                mask_s = mask
                ctx_s = ctx
                # generate and decode the a subset of the current training batch
                for jj in xrange(numpy.minimum(10, len(caps))):
                    sample, score = gen_sample(tparams, f_init, f_next, ctx_s[jj], model_options,
                                               trng=trng, k=5, maxlen=30, stochastic=False)
                    # Decode the sample from encoding back to words
                    print 'Truth ',jj,': ',
                    for vv in x_s[:,jj]:
                        if vv == 0:
                            break
                        if vv in word_idict:
                            print word_idict[vv],
                        else:
                            print 'UNK',
                    print
                    for kk, ss in enumerate([sample[0]]):
                        print 'Sample (', kk,') ', jj, ': ',
                        for vv in ss:
                            if vv == 0:
                                break
                            if vv in word_idict:
                                print word_idict[vv],
                            else:
                                print 'UNK',
                    print

            # Log validation loss + checkpoint the model with the best validation log likelihood
            if numpy.mod(uidx, validFreq) == 0:
                use_noise.set_value(0.)
                train_err = 0
                valid_err = 0
                test_err = 0

                if valid:
                    valid_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, valid, kf_valid).mean()
                if test:
                    test_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, test, kf_test).mean()

                history_errs.append([valid_err, test_err])

                # the model with the best validation long likelihood is saved seperately with a different name
                if uidx == 0 or valid_err <= numpy.array(history_errs)[:,0].min():
                    best_p = unzip(tparams)
                    print 'Saving model with best validation ll'
                    params = copy.copy(best_p)
                    params = unzip(tparams)
                    numpy.savez(saveto+'_bestll', history_errs=history_errs, **params)
                    bad_counter = 0

                # abort training if perplexity has been increasing for too long
                if eidx > patience and len(history_errs) > patience and valid_err >= numpy.array(history_errs)[:-patience,0].min():
                    bad_counter += 1
                    if bad_counter > patience:
                        print 'Early Stop!'
                        estop = True
                        break

                print 'Train ', train_err, 'Valid ', valid_err, 'Test ', test_err

        print 'Seen %d samples' % n_samples

        if estop:
            break

        if save_per_epoch:
            numpy.savez(saveto + '_epoch_' + str(eidx + 1), history_errs=history_errs, **unzip(tparams))

    # use the best nll parameters for final checkpoint (if they exist)
    if best_p is not None:
        zipp(best_p, tparams)

    use_noise.set_value(0.)
    train_err = 0
    valid_err = 0
    test_err = 0
    if valid:
        valid_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, valid, kf_valid)
    if test:
        test_err = -pred_probs(f_log_probs, model_options, worddict, prepare_data, test, kf_test)

    print 'Train ', train_err, 'Valid ', valid_err, 'Test ', test_err

    params = copy.copy(best_p)
    numpy.savez(saveto, zipped_params=best_p, train_err=train_err,
                valid_err=valid_err, test_err=test_err, history_errs=history_errs,
                **params)

    return train_err, valid_err, test_err
Esempio n. 16
0
def gen_model(queue, rqueue, pid, model, options, k, normalize, word_idict,
              sampling):
    import theano
    from theano import tensor
    from theano.sandbox.rng_mrg import MRG_RandomStreams as RandomStreams

    trng = RandomStreams(1234)
    # this is zero indicate we are not using dropout in the graph
    use_noise = theano.shared(numpy.float32(0.), name='use_noise')

    # tparams_list = []
    # f_init_list = []
    # f_next_list = []

    # for m in model:
    #     params = init_params(options)
    #     params = load_params(m, params)
    #     tparams_list.append( init_tparams(params) )
    #     f_init, f_next = build_sampler(tparams_list[-1], options, use_noise, trng, sampling=sampling)
    #     f_init_list.append( f_init )
    #     f_next_list.append( f_next )

    # get the parameters
    params = init_params(options)
    params = load_params(model, params)
    tparams = init_tparams(params)

    # build the sampling computational graph
    # see capgen.py for more detailed explanations
    f_init, f_next = build_sampler(tparams,
                                   options,
                                   use_noise,
                                   trng,
                                   sampling=sampling)

    def _gencap(cc0):
        sample, score = gen_sample(tparams,
                                   f_init,
                                   f_next,
                                   cc0,
                                   options,
                                   trng=trng,
                                   k=k,
                                   maxlen=200,
                                   stochastic=False)

        #sample, score = gen_sample(tparams, f_init, f_next, cc0, options,
        #                           trng=trng, k=k, maxlen=200, stochastic=False)
        # adjust for length bias
        #if normalize:
        lengths = numpy.array([len(s) for s in sample])
        score = score / lengths
        sidx = numpy.argmin(score)
        return sample[sidx], score[sidx]

    while True:
        req = queue.get()
        # exit signal
        if req is None:
            break
        idx, context = req[0], req[1]
        print pid, '-', idx
        seq, score = _gencap(context)
        rqueue.put((idx, seq, score))

    return
def train(
    dim_word=300,  # word vector dimensionality
    ctx_dim=300,  # context vector dimensionality
    semantic_dim=300,
    dim=1000,  # the number of LSTM units
    cnn_dim=4096,  # CNN feature dimension
    n_layers_att=1,  # number of layers used to compute the attention weights
    n_layers_out=1,  # number of layers used to compute logit
    n_layers_lstm=1,  # number of lstm layers
    n_layers_init=1,  # number of layers to initialize LSTM at time 0
    lstm_encoder=True,  # if True, run bidirectional LSTM on input units
    prev2out=False,  # Feed previous word into logit
    ctx2out=False,  # Feed attention weighted ctx into logit
    cutoff=10,
    patience=5,
    max_epochs=30,
    dispFreq=500,
    decay_c=0.,  # weight decay coeff
    alpha_c=0.,  # doubly stochastic coeff
    lrate=1e-4,  # used only for SGD
    selector=False,  # selector (see paper)
    maxlen=30,  # maximum length of the description
    optimizer='rmsprop',
    pretrained='',
    batch_size=256,
    saveto='model',  # relative path of saved model file
    saveFreq=1000,  # save the parameters after every saveFreq updates
    sampleFreq=100,  # generate some samples after every sampleFreq updates
    embedding='../Data/GloVe/vocab_glove.pkl',
    cnn_type='vgg',
    prefix='../Data',  # path to find data
    dataset='coco',
    criterion='Bleu_4',
    switch_test_val=False,
    use_cnninit=True,
    use_dropout=True,  # setting this true turns on dropout at various points
    use_dropout_lstm=False,  # dropout on lstm gates
    save_per_epoch=False):  # this saves down the model every epoch

    # hyperparam dict
    model_options = locals().copy()
    model_options = validate_options(model_options)

    # reload options
    if os.path.exists('%s.pkl' % saveto):
        print "Reloading options"
        with open('%s.pkl' % saveto, 'rb') as f:
            model_options = pkl.load(f)

    print "Using the following parameters:"
    print model_options

    print 'Loading data'
    load_data, prepare_data = get_dataset(model_options['dataset'])

    # Load data from data path
    if 'switch_test_val' in model_options and model_options['switch_test_val']:
        train, valid, worddict = load_data(path=osp.join(
            model_options['prefix'], model_options['dataset']),
                                           options=model_options,
                                           load_train=True,
                                           load_test=True)
    else:
        train, valid, worddict = load_data(path=osp.join(
            model_options['prefix'], model_options['dataset']),
                                           options=model_options,
                                           load_train=True,
                                           load_val=True)

    # Automatically calculate the update frequency
    validFreq = len(train[0]) / model_options['batch_size']
    print "Validation frequency is %d" % validFreq

    word_idict = {vv: kk for kk, vv in worddict.iteritems()}
    model_options['n_words'] = len(worddict)

    # Initialize (or reload) the parameters using 'model_options'
    # then build the Theano graph
    print 'Building model'
    params = init_params(model_options)
    # Initialize it with glove
    if 'VCemb' in params:
        params['VCemb'] = read_pkl(
            model_options['embedding']).astype('float32')

    # If there is a same experiment, don't use pretrained weights
    if os.path.exists('%s.npz' % saveto):
        print "Reloading model"
        params = load_params('%s.npz' % saveto, params)
    elif pretrained != '':
        params = load_params(pretrained, params,
                             False)  # Only pretrain the Language model

    # numpy arrays -> theano shared variables
    tparams = init_tparams(params)

    # In order, we get:
    #   1) trng - theano random number generator
    #   2) use_noise - flag that turns on dropout
    #   3) inps - inputs for f_grad_shared
    #   4) cost - log likelihood for each sentence
    #   5) opts_out - optional outputs (e.g selector)
    trng, use_noise, \
          inps, alphas,\
          cost, \
          opt_outs = \
          build_model(tparams, model_options)

    # Load evaluator to calculate bleu score
    evaluator = cocoEvaluation(model_options['dataset'])

    # To sample, we use beam search: 1) f_init is a function that initializes
    # the LSTM at time 0 [see top right of page 4], 2) f_next returns the distribution over
    # words and also the new "initial state/memory" see equation
    print 'Building sampler'
    f_init, f_next = build_sampler(tparams, model_options, use_noise, trng)

    # we want the cost without any the regularizers
    # define the log probability
    f_log_probs = theano.function(inps,
                                  -cost,
                                  profile=False,
                                  updates=None,
                                  allow_input_downcast=True)

    # Define the cost function + Regularization
    cost = cost.mean()
    # add L2 regularization costs
    if decay_c > 0.:
        decay_c = theano.shared(numpy.float32(decay_c), name='decay_c')
        weight_decay = 0.
        for kk, vv in tparams.iteritems():
            weight_decay += (vv**2).sum()
        weight_decay *= decay_c
        cost += weight_decay

    # Doubly stochastic regularization
    if alpha_c > 0.:
        alpha_c = theano.shared(numpy.float32(alpha_c), name='alpha_c')
        alpha_reg = sum([
            alpha_c * ((1. - alpha.sum(0))**2).sum(0).mean()
            for alpha in alphas
        ])
        cost += alpha_reg

    # Backprop!
    grads = tensor.grad(cost, wrt=itemlist(tparams))
    # to getthe cost after regularization or the gradients, use this

    # f_grad_shared computes the cost and updates adaptive learning rate variables
    # f_update updates the weights of the model
    lr = tensor.scalar(name='lr')
    f_grad_shared, f_update = eval(model_options['optimizer'])(lr, tparams,
                                                               grads, inps,
                                                               cost)

    print 'Optimization'
    train_iter = HomogeneousData(train,
                                 batch_size=batch_size,
                                 maxlen=model_options['maxlen'])

    # history_bleu is a bare-bones training log, reload history
    history_bleu = []
    if os.path.exists('%s.npz' % saveto):
        history_bleu = numpy.load('%s.npz' % saveto)['history_bleu'].tolist()
    start_epochs = len(history_bleu)
    best_p = None
    bad_counter = 0

    if validFreq == -1:
        validFreq = len(train[0]) / batch_size
    if saveFreq == -1:
        saveFreq = len(train[0]) / batch_size
    if sampleFreq == -1:
        sampleFreq = len(train[0]) / batch_size

    uidx = 0
    estop = False
    for eidx in xrange(start_epochs, model_options['max_epochs']):
        n_samples = 0

        print 'Epoch ', eidx

        for caps in train_iter:
            n_samples += len(caps)
            uidx += 1
            # turn on dropout
            use_noise.set_value(1.)

            # preprocess the caption, recording the
            # time spent to help detect bottlenecks
            pd_start = time.time()
            x, mask, ctx, cnn_feats = prepare_data(caps, train[1], train[2],
                                                   worddict, model_options)
            pd_duration = time.time() - pd_start

            if x is None:
                print 'Minibatch with zero sample under length ', model_options[
                    'maxlen']
                continue

            # get the cost for the minibatch, and update the weights
            ud_start = time.time()
            cost = f_grad_shared(x, mask, ctx, cnn_feats)

            print "Epoch %d, Updates: %d, Cost is: %f" % (eidx, uidx, cost)

            f_update(model_options['lrate'])
            ud_duration = time.time(
            ) - ud_start  # some monitoring for each mini-batch

            # Numerical stability check
            if numpy.isnan(cost) or numpy.isinf(cost):
                print 'NaN detected'
                return 1., 1., 1.

            if numpy.mod(uidx, dispFreq) == 0:
                print 'Epoch ', eidx, 'Update ', uidx, 'Cost ', cost, 'PD ', pd_duration, 'UD ', ud_duration

            # Print a generated sample as a sanity check
            if numpy.mod(uidx, model_options['sampleFreq']) == 0:
                # turn off dropout first
                use_noise.set_value(0.)
                x_s = x
                mask_s = mask
                ctx_s = ctx
                # generate and decode the a subset of the current training batch
                for jj in xrange(numpy.minimum(10, len(caps))):
                    sample, score, alphas = gen_sample(
                        f_init,
                        f_next,
                        ctx_s[jj],
                        cnn_feats[jj],
                        model_options,
                        trng=trng,
                        maxlen=model_options['maxlen'])
                    # Decode the sample from encoding back to words
                    print 'Truth ', jj, ': ',
                    print seqs2words(x_s[:, jj], word_idict)
                    for kk, ss in enumerate([sample[0]]):
                        print 'Sample (', kk, ') ', jj, ': ',
                        print seqs2words(ss, word_idict)

            # Log validation loss + checkpoint the model with the best validation log likelihood
            if numpy.mod(uidx, validFreq) == 0:
                use_noise.set_value(0.)

                # Do evaluation on validation set
                imgid = collapse([elem[-1] for elem in valid[0]])
                caps = process_examples([f_init], [f_next], imgid, valid[1],
                                        valid[2], word_idict, model_options)
                folder = osp.join('../output', '%s_%s' % (saveto, 'val'))
                if not osp.exists(folder):
                    os.mkdir(folder)
                with open(osp.join(folder, 'captions_val2014_results.json'),
                          'w') as f:
                    json.dump(caps, f)
                eva_result = evaluator.evaluate(folder, False)
                if model_options['criterion'] == 'combine':
                    history_bleu.append(eva_result['Bleu_4'] +
                                        eva_result['CIDEr'])
                else:
                    history_bleu.append(eva_result[model_options['criterion']])

                # the model with the best validation long likelihood is saved seperately with a different name
                if uidx == 0 or history_bleu[-1] == max(history_bleu):
                    best_p = unzip(tparams)
                    print 'Saving model with best validation ll'
                    params = copy.copy(best_p)
                    params = unzip(tparams)
                    numpy.savez(saveto + '_bestll',
                                history_bleu=history_bleu,
                                **params)
                    bad_counter = 0

                # abort training if perplexity has been increasing for too long
                if len(history_bleu) > model_options[
                        'patience'] and history_bleu[-1] <= max(
                            history_bleu[:-model_options['patience']]):
                    bad_counter += 1
                    if bad_counter > model_options['patience']:
                        print 'Early Stop!'
                        estop = True
                        break

                print ' BLEU-4 score ', history_bleu[-1]

            # Checkpoint
            if numpy.mod(uidx, model_options['saveFreq']) == 0:
                print 'Saving...',

                if best_p is not None:
                    params = copy.copy(best_p)
                else:
                    params = unzip(tparams)
                numpy.savez(saveto, history_bleu=history_bleu, **params)
                pkl.dump(model_options, open('%s.pkl' % saveto, 'wb'))
                print 'Done'

        print 'Seen %d samples' % n_samples

        if estop:
            break

        if model_options['save_per_epoch']:
            numpy.savez(saveto + '_epoch_' + str(eidx + 1),
                        history_bleu=history_bleu,
                        **unzip(tparams))

    # use the best nll parameters for final checkpoint (if they exist)
    if best_p is not None:
        zipp(best_p, tparams)
    params = copy.copy(best_p)
    numpy.savez(saveto,
                zipped_params=best_p,
                history_bleu=history_bleu,
                **params)