Esempio n. 1
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def run():
    train_images, train_labels, _, _, _ = load_data()
    train_images = train_images[:N_data, :]
    train_labels = train_labels[:N_data, :]
    batch_idxs = BatchList(N_data, batch_size)
    iter_per_epoch = len(batch_idxs)
    N_weights, _, loss_fun, frac_err = make_nn_funs(layer_sizes, L2_reg)

    def indexed_loss_fun(w, idxs):
        return loss_fun(w, X=train_images[idxs], T=train_labels[idxs])

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)
    npr.seed(1)
    V0 = npr.randn(N_weights) * velocity_scale
    W0 = npr.randn(N_weights) * np.exp(log_param_scale)
    output = []
    for i in range(N_meta_iter):
        print "Meta iteration {0}".format(i)
        results = sgd(indexed_loss_fun,
                      batch_idxs,
                      N_iters,
                      W0,
                      V0,
                      np.exp(log_alphas),
                      betas,
                      record_learning_curve=True)
        learning_curve = results['learning_curve']
        d_log_alphas = np.exp(log_alphas) * results['d_alphas']
        output.append((learning_curve, log_alphas, d_log_alphas))
        log_alphas = log_alphas - meta_alpha * d_log_alphas

    return output
Esempio n. 2
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def run():
    train_images, train_labels, _, _, _ = load_data()
    train_images = train_images[:N_data, :]
    train_labels = train_labels[:N_data, :]
    batch_idxs = BatchList(N_data, batch_size)
    iter_per_epoch = len(batch_idxs)
    N_weights, _, loss_fun, frac_err = make_nn_funs(layer_sizes, L2_reg)

    def indexed_loss_fun(w, idxs):
        return loss_fun(w, X=train_images[idxs], T=train_labels[idxs])

    V0 = npr.randn(N_weights) * velocity_scale
    losses = []
    d_losses = []
    for N_iters in all_N_iters:
        alphas = np.full(N_iters, alpha_0)
        betas = np.full(N_iters, beta_0)
        loss_curve = []
        d_loss_curve = []
        for log_param_scale in all_log_param_scale:
            print "log_param_scale {0}, N_iters {1}".format(
                log_param_scale, N_iters)
            npr.seed(1)
            W0 = npr.randn(N_weights) * np.exp(log_param_scale)
            results = sgd(indexed_loss_fun, batch_idxs, N_iters, W0, V0,
                          alphas, betas)
            loss_curve.append(results['loss_final'])
            d_loss_curve.append(d_log_loss(W0, results['d_x']))
        losses.append(loss_curve)
        d_losses.append(d_loss_curve)

    with open('results.pkl', 'w') as f:
        pickle.dump((losses, d_losses), f)
Esempio n. 3
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def run(oiter):
    # ----- Variable for this run -----
    log_alpha_0 = all_log_alpha_0[oiter]

    print "Running job {0} on {1}".format(oiter + 1, socket.gethostname())
    train_images, train_labels, _, _, _ = load_data()
    train_images = train_images[:N_data, :]
    train_labels = train_labels[:N_data, :]
    batch_idxs = BatchList(N_data, batch_size)
    iter_per_epoch = len(batch_idxs)
    N_weights, _, loss_fun, frac_err = make_nn_funs(layer_sizes, L2_reg)

    def indexed_loss_fun(w, idxs):
        return loss_fun(w, X=train_images[idxs], T=train_labels[idxs])

    V0 = npr.randn(N_weights) * velocity_scale
    losses = []
    d_losses = []
    alpha_0 = np.exp(log_alpha_0)
    for N_iters in all_N_iters:
        alphas = np.full(N_iters, alpha_0)
        betas = np.full(N_iters, beta_0)
        npr.seed(1)
        W0 = npr.randn(N_weights) * np.exp(log_param_scale)
        results = sgd(indexed_loss_fun, batch_idxs, N_iters, W0, V0, alphas,
                      betas)
        losses.append(results['loss_final'])
        d_losses.append(d_log_loss(alpha_0, results['d_alphas']))

    return losses, d_losses
Esempio n. 4
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def run():
    (train_images, train_labels), (val_images, val_labels), (test_images, test_labels) \
        = load_data_subset(N_train_data, N_val_data, N_test_data)

    batch_idxs = BatchList(N_train_data, batch_size)
    parser, _, loss_fun, frac_err = make_nn_funs(layer_sizes)
    N_weights = parser.N

    hyperparser = WeightsParser()
    hyperparser.add_weights('log_L2_reg', (N_weights, ))
    metas = np.zeros(hyperparser.N)
    print "Number of hyperparameters to be trained:", hyperparser.N

    npr.seed(0)
    hyperparser.set(metas, 'log_L2_reg', log_L2_reg_scale + np.ones(N_weights))

    def indexed_loss_fun(x, meta_params, idxs):  # To be optimized by SGD.
        L2_reg = np.exp(hyperparser.get(meta_params, 'log_L2_reg'))
        return loss_fun(x,
                        X=train_images[idxs],
                        T=train_labels[idxs],
                        L2_reg=L2_reg)

    def meta_loss_fun(x, meta_params):  # To be optimized in the outer loop.
        L2_reg = np.exp(hyperparser.get(meta_params, 'log_L2_reg'))
        log_prior = -meta_L2_reg * np.dot(L2_reg.ravel(), L2_reg.ravel())
        return loss_fun(x, X=val_images, T=val_labels) - log_prior

    def test_loss_fun(x):  # To measure actual performance.
        return loss_fun(x, X=test_images, T=test_labels)

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)

    v0 = npr.randn(N_weights) * velocity_scale
    x0 = npr.randn(N_weights) * np.exp(log_param_scale)

    output = []
    for i in range(N_meta_iter):
        results = sgd2(indexed_loss_fun, meta_loss_fun, batch_idxs, N_iters,
                       x0, v0, np.exp(log_alphas), betas, metas)

        learning_curve = results['learning_curve']
        validation_loss = results['M_final']
        test_loss = test_loss_fun(results['x_final'])
        weightparser = parser.new_vect(results['x_final'])
        l2parser = parser.new_vect(np.exp(hyperparser.get(metas,
                                                          'log_L2_reg')))
        output.append((learning_curve, validation_loss, test_loss,
                       weightparser[('weights', 0)], l2parser[('weights', 0)]))
        metas -= results['dMd_meta'] * meta_stepsize
        print "Meta iteration {0} Valiation loss {1} Test loss {2}"\
            .format(i, validation_loss, test_loss)
    return output
Esempio n. 5
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def test_sgd2():
    N_weights = 5
    W0 = 0.1 * npr.randn(N_weights)
    V0 = 0.1 * npr.randn(N_weights)
    N_data = 12
    batch_size = 4
    num_epochs = 3
    batch_idxs = BatchList(N_data, batch_size)
    N_iter = num_epochs * len(batch_idxs)
    alphas = 0.1 * npr.rand(len(batch_idxs) * num_epochs)
    betas = 0.5 + 0.2 * npr.rand(len(batch_idxs) * num_epochs)
    meta = 0.1 * npr.randn(N_weights * 2)

    A = npr.randn(N_data, N_weights)

    def loss_fun(W, meta, idxs):
        sub_A = A[idxs, :]
        return np.dot(
            np.dot(W + meta[:N_weights] + meta[N_weights:],
                   np.dot(sub_A.T, sub_A)), W)

    def meta_loss_fun(w, meta):
        return np.dot(w, w) + np.dot(meta, meta)

    def full_loss(W0, V0, alphas, betas, meta):
        result = sgd2(loss_fun, meta_loss_fun, batch_idxs, N_iter, W0, V0,
                      alphas, betas, meta)
        return result['L_final']

    def meta_loss(W0, V0, alphas, betas, meta):
        result = sgd2(loss_fun, meta_loss_fun, batch_idxs, N_iter, W0, V0,
                      alphas, betas, meta)
        return result['M_final']

    result = sgd2(loss_fun, meta_loss_fun, batch_idxs, N_iter, W0, V0, alphas,
                  betas, meta)

    d_an = (result['dLd_x'], result['dLd_v'], result['dLd_alphas'],
            result['dLd_betas'], result['dLd_meta'])
    d_num = nd(full_loss, W0, V0, alphas, betas, meta)
    for i, (an, num) in enumerate(zip(d_an, d_num)):
        assert np.allclose(an, num, rtol=1e-3, atol=1e-4), \
            "Type {0}, diffs are: {1}".format(i, an - num)
        print "Type {0}, diffs are: {1}".format(i, an - num)

    d_an = (result['dMd_x'], result['dMd_v'], result['dMd_alphas'],
            result['dMd_betas'], result['dMd_meta'])
    d_num = nd(meta_loss, W0, V0, alphas, betas, meta)
    for i, (an, num) in enumerate(zip(d_an, d_num)):
        assert np.allclose(an, num, rtol=1e-3, atol=1e-4), \
            "Type {0}, diffs are: {1}".format(i, an - num)
        print "Type {0}, diffs are: {1}".format(i, an - num)
Esempio n. 6
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def run():
    val_images, val_labels, test_images, test_labels, _ = load_data(
        normalize=True)
    val_images = val_images[:N_val_data, :]
    val_labels = val_labels[:N_val_data, :]
    truedatasize = np.std(val_images)

    test_images = test_images[:N_test_data, :]
    test_labels = test_labels[:N_test_data, :]
    batch_idxs = BatchList(N_fake_data, batch_size)
    parser, _, loss_fun, frac_err = make_nn_funs(layer_sizes,
                                                 L2_reg,
                                                 return_parser=True)
    N_weights = parser.N

    fake_data = npr.randn(
        *(val_images[:N_fake_data, :].shape)) * init_fake_data_scale
    fake_labels = one_hot(np.array(range(N_fake_data)) % N_classes,
                          N_classes)  # One of each.

    def indexed_loss_fun(x, meta_params, idxs):  # To be optimized by SGD.
        return loss_fun(x, X=meta_params[idxs], T=fake_labels[idxs])

    def meta_loss_fun(x, meta_params):  # To be optimized in the outer loop.
        log_prior = -fake_data_L2_reg * np.dot(meta_params.ravel(),
                                               meta_params.ravel())
        return loss_fun(x, X=val_images, T=val_labels) - log_prior

    def test_loss_fun(x):  # To measure actual performance.
        return loss_fun(x, X=test_images, T=test_labels)

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)
    npr.seed(0)
    v0 = npr.randn(N_weights) * velocity_scale
    x0 = npr.randn(N_weights) * np.exp(log_param_scale)

    output = []
    for i in range(N_meta_iter):
        results = sgd2(indexed_loss_fun, meta_loss_fun, batch_idxs, N_iters,
                       x0, v0, np.exp(log_alphas), betas, fake_data)
        learning_curve = results['learning_curve']
        validation_loss = results['M_final']
        fakedatasize = np.std(fake_data) / truedatasize
        test_loss = test_loss_fun(results['x_final'])
        output.append((learning_curve, validation_loss, test_loss, fake_data,
                       fakedatasize))
        fake_data -= results[
            'dMd_meta'] * data_stepsize  # Update data with one gradient step.
        print "Meta iteration {0} Valiation loss {1} Test loss {2}"\
            .format(i, validation_loss, test_loss)
    return output
Esempio n. 7
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def test_sgd_parser():
    N_weights = 6
    W0 = 0.1 * npr.randn(N_weights)
    N_data = 12
    batch_size = 4
    num_epochs = 4
    batch_idxs = BatchList(N_data, batch_size)

    parser = VectorParser()
    parser.add_shape('first', [
        2,
    ])
    parser.add_shape('second', [
        1,
    ])
    parser.add_shape('third', [
        3,
    ])
    N_weight_types = 3

    alphas = 0.1 * npr.rand(len(batch_idxs) * num_epochs, N_weight_types)
    betas = 0.5 + 0.2 * npr.rand(len(batch_idxs) * num_epochs, N_weight_types)
    meta = 0.1 * npr.randn(N_weights * 2)

    A = npr.randn(N_data, N_weights)

    def loss_fun(W, meta, i=None):
        idxs = batch_idxs.all_idxs if i is None else batch_idxs[
            i % len(batch_idxs)]
        sub_A = A[idxs, :]
        return np.dot(
            np.dot(W + meta[:N_weights] + meta[N_weights:],
                   np.dot(sub_A.T, sub_A)), W)

    def full_loss(params):
        (W0, alphas, betas, meta) = params
        result = sgd_parsed(grad(loss_fun), kylist(W0, alphas, betas, meta),
                            parser)
        return loss_fun(result, meta)

    d_num = nd(full_loss, (W0, alphas, betas, meta))
    d_an_fun = grad(full_loss)
    d_an = d_an_fun([W0, alphas, betas, meta])
    for i, (an, num) in enumerate(zip(d_an, d_num[0])):
        assert np.allclose(an, num, rtol=1e-3, atol=1e-4), \
            "Type {0}, diffs are: {1}".format(i, an - num)
Esempio n. 8
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def run():
    train_images, train_labels, _, _, _ = load_data(normalize=True)
    train_images = train_images[:N_real_data, :]
    train_labels = train_labels[:N_real_data, :]
    batch_idxs = BatchList(N_fake_data, batch_size)
    parser, _, loss_fun, frac_err = make_nn_funs(layer_sizes,
                                                 L2_reg,
                                                 return_parser=True)
    N_weights = parser.N

    #fake_data = npr.randn(*(train_images[:N_fake_data, :].shape))
    fake_data = np.zeros(train_images[:N_fake_data, :].shape)
    one_hot = lambda x, K: np.array(x[:, None] == np.arange(K)[None, :],
                                    dtype=int)
    fake_labels = one_hot(np.array(range(0, 10)), 10)  # One of each label.

    def indexed_loss_fun(x, meta_params, idxs):  # To be optimized by SGD.
        return loss_fun(x, X=meta_params[idxs], T=fake_labels[idxs])

    def meta_loss_fun(x):  # To be optimized in the outer loop.
        return loss_fun(x, X=train_images, T=train_labels)

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)
    npr.seed(0)
    v0 = npr.randn(N_weights) * velocity_scale
    x0 = npr.randn(N_weights) * np.exp(log_param_scale)

    output = []
    for i in range(N_meta_iter):
        print "Meta iteration {0}".format(i)
        results = sgd2(indexed_loss_fun, meta_loss_fun, batch_idxs, N_iters,
                       x0, v0, np.exp(log_alphas), betas, fake_data)

        learning_curve = results['learning_curve']
        output.append((learning_curve, fake_data))
        fake_data -= results[
            'dMd_meta'] * data_stepsize  # Update data with one gradient step.

    return output
Esempio n. 9
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def run():
    train_images, train_labels, _, _, _ = load_data()
    train_images = train_images[:N_data, :]
    train_labels = train_labels[:N_data, :]
    batch_idxs = BatchList(N_data, batch_size)
    iter_per_epoch = len(batch_idxs)
    N_weights, _, loss_fun, frac_err = make_nn_funs(layer_sizes, L2_reg)

    def indexed_loss_fun(w, idxs):
        return loss_fun(w, X=train_images[idxs], T=train_labels[idxs])

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)
    npr.seed(2)
    V0 = npr.randn(N_weights) * velocity_scale
    #W0 = npr.randn(N_weights) * np.exp(log_param_scale)
    bins = np.linspace(-1, 1, N_bins) * np.exp(log_param_scale)
    W_uniform = npr.rand(N_weights)
    output = []
    for i in range(N_meta_iter):
        print "Meta iteration {0}".format(i)
        W0, dW_dbins = bininvcdf(W_uniform, bins)
        results = sgd(indexed_loss_fun,
                      batch_idxs,
                      N_iters,
                      W0,
                      V0,
                      np.exp(log_alphas),
                      betas,
                      record_learning_curve=True)
        dL_dx = results['d_x']
        dL_dbins = np.dot(dL_dx, dW_dbins)
        learning_curve = results['learning_curve']
        output.append((learning_curve, bins))
        bins = bins - dL_dbins * bin_stepsize
        bins[[0, -1]] = bins[[0, -1]] - dL_dbins[[0, 1]] * bin_stepsize
        bins.sort()  # Sort in place.

    return output
Esempio n. 10
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def run():
    val_images, val_labels, test_images, test_labels, _ = load_data(
        normalize=True)
    val_images = val_images[:N_val_data, :]
    val_labels = val_labels[:N_val_data, :]
    true_data_scale = np.std(val_images)

    test_images = test_images[:N_test_data, :]
    test_labels = test_labels[:N_test_data, :]
    batch_idxs = BatchList(N_fake_data, batch_size)
    parser, _, loss_fun, frac_err = make_nn_funs(layer_sizes)
    N_weights = len(parser.vect)

    npr.seed(0)
    init_fake_data = npr.randn(
        *(val_images[:N_fake_data, :].shape)) * init_fake_data_scale
    one_hot = lambda x, K: np.array(x[:, None] == np.arange(K)[None, :],
                                    dtype=int)
    fake_labels = one_hot(np.array(range(N_fake_data)) % N_classes,
                          N_classes)  # One of each.

    hyperparser = WeightsParser()
    hyperparser.add_weights('log_L2_reg', (1, ))
    hyperparser.add_weights('fake_data', init_fake_data.shape)
    metas = np.zeros(hyperparser.N)
    print "Number of hyperparameters to be trained:", hyperparser.N
    hyperparser.set(metas, 'log_L2_reg', init_log_L2_reg)
    hyperparser.set(metas, 'fake_data', init_fake_data)

    def indexed_loss_fun(x, meta_params, idxs):  # To be optimized by SGD.
        L2_reg = np.exp(hyperparser.get(meta_params, 'log_L2_reg')[0])
        fake_data = hyperparser.get(meta_params, 'fake_data')
        return loss_fun(x,
                        X=fake_data[idxs],
                        T=fake_labels[idxs],
                        L2_reg=L2_reg)

    def meta_loss_fun(x, meta_params):  # To be optimized in the outer loop.
        fake_data = hyperparser.get(meta_params, 'fake_data')
        log_prior = -fake_data_L2_reg * np.dot(fake_data.ravel(),
                                               fake_data.ravel())
        return loss_fun(x, X=val_images, T=val_labels) - log_prior

    def test_loss_fun(x):  # To measure actual performance.
        return loss_fun(x, X=test_images, T=test_labels)

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)

    output = []
    velocity = np.zeros(hyperparser.N)
    for i in range(N_meta_iter):
        print "L2 reg is ", np.exp(hyperparser.get(metas,
                                                   'log_L2_reg')[0]), "| ",

        npr.seed(0)
        v0 = npr.randn(N_weights) * velocity_scale
        x0 = npr.randn(N_weights) * np.exp(log_param_scale)

        results = sgd2(indexed_loss_fun, meta_loss_fun, batch_idxs, N_iters,
                       x0, v0, np.exp(log_alphas), betas, metas)

        learning_curve = results['learning_curve']
        validation_loss = results['M_final']
        test_err = frac_err(results['x_final'], test_images, test_labels)
        fake_data_scale = np.std(hyperparser.get(
            metas, 'fake_data')) / true_data_scale
        test_loss = test_loss_fun(results['x_final'])
        output.append(
            (learning_curve, validation_loss, test_loss, fake_data_scale,
             np.exp(hyperparser.get(metas, 'log_L2_reg')[0]), test_err))

        # Do meta-SGD with momentum
        g = results['dMd_meta']
        velocity = meta_momentum * velocity - (1.0 - meta_momentum) * g
        metas += velocity * meta_stepsize
        print "Meta iteration {0} Validation loss {1} Test loss {2} Test err {3}"\
            .format(i, validation_loss, test_loss, test_err)
    return output, hyperparser.get(metas, 'fake_data')
Esempio n. 11
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def run():
    (train_images, train_labels),\
    (valid_images, valid_labels),\
    (tests_images, tests_labels) = load_data_subset(N_train, N_valid, N_tests)
    batch_idxs = BatchList(N_train, batch_size)
    N_iters = N_epochs * len(batch_idxs)
    parser, pred_fun, loss_fun, frac_err = make_nn_funs(layer_sizes)
    N_weight_types = len(parser.names)
    hyperparams = VectorParser()
    hyperparams['log_L2_reg'] = np.full(N_weight_types, init_log_L2_reg)
    hyperparams['log_param_scale'] = np.full(N_weight_types,
                                             init_log_param_scale)
    hyperparams['log_alphas'] = np.full(N_iters, init_log_alphas)
    hyperparams['invlogit_betas'] = np.full(N_iters, init_invlogit_betas)

    def indexed_loss_fun(w, log_L2_reg, i):
        idxs = batch_idxs[i % len(batch_idxs)]
        partial_vects = [
            np.full(parser[name].size, np.exp(log_L2_reg[i]))
            for i, name in enumerate(parser.names)
        ]
        L2_reg_vect = np.concatenate(partial_vects, axis=0)
        return loss_fun(w,
                        X=train_images[idxs],
                        T=train_labels[idxs],
                        L2_reg=L2_reg_vect)

    def train_loss_fun(w, log_L2_reg=0.0):
        return loss_fun(w, X=train_images, T=train_labels)

    def valid_loss_fun(w, log_L2_reg=0.0):
        return loss_fun(w, X=valid_images, T=valid_labels)

    def tests_loss_fun(w, log_L2_reg=0.0):
        return loss_fun(w, X=tests_images, T=tests_labels)

    all_learning_curves = []
    all_x = []

    def hyperloss_grad(hyperparam_vect, i):
        learning_curve = []

        def callback(x, i):
            if i % len(batch_idxs) == 0:
                learning_curve.append(
                    loss_fun(x, X=train_images, T=train_labels))

        npr.seed(i)
        N_weights = parser.vect.size
        V0 = np.zeros(N_weights)

        cur_hyperparams = hyperparams.new_vect(hyperparam_vect)
        layer_param_scale = [
            np.full(parser[name].size,
                    np.exp(cur_hyperparams['log_param_scale'][i]))
            for i, name in enumerate(parser.names)
        ]
        W0 = npr.randn(N_weights) * np.concatenate(layer_param_scale, axis=0)
        alphas = np.exp(cur_hyperparams['log_alphas'])
        betas = logit(cur_hyperparams['invlogit_betas'])
        log_L2_reg = cur_hyperparams['log_L2_reg']
        results = sgd3(indexed_loss_fun,
                       valid_loss_fun,
                       W0,
                       V0,
                       alphas,
                       betas,
                       log_L2_reg,
                       callback=callback)
        hypergrads = hyperparams.copy()
        hypergrads['log_L2_reg'] = results['dMd_meta']
        weights_grad = parser.new_vect(W0 * results['dMd_x'])
        hypergrads['log_param_scale'] = [
            np.sum(weights_grad[name]) for name in parser.names
        ]
        hypergrads['log_alphas'] = results['dMd_alphas'] * alphas
        hypergrads['invlogit_betas'] = (
            results['dMd_betas'] * d_logit(cur_hyperparams['invlogit_betas']))
        all_x.append(results['x_final'])
        all_learning_curves.append(learning_curve)
        return hypergrads.vect

    add_fields = ['train_loss', 'valid_loss', 'tests_loss']
    meta_results = {field: [] for field in add_fields + hyperparams.names}

    def meta_callback(hyperparam_vect, i):
        print "Meta iter {0}".format(i)
        x = all_x[-1]
        cur_hyperparams = hyperparams.new_vect(hyperparam_vect.copy())
        log_L2_reg = cur_hyperparams['log_L2_reg']
        for field in cur_hyperparams.names:
            meta_results[field].append(cur_hyperparams[field])

        meta_results['train_loss'].append(train_loss_fun(x))
        meta_results['valid_loss'].append(valid_loss_fun(x))
        meta_results['tests_loss'].append(tests_loss_fun(x))

    final_result = rms_prop(hyperloss_grad, hyperparams.vect, meta_callback,
                            N_meta_iter, meta_alpha)
    meta_results['all_learning_curves'] = all_learning_curves
    parser.vect = None  # No need to pickle zeros
    return meta_results, parser
Esempio n. 12
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def run():
    train_images, train_labels, _, _, _ = load_data(normalize=True)
    train_images = train_images[:N_data, :]
    train_labels = train_labels[:N_data, :]
    batch_idxs = BatchList(N_data, batch_size)
    iter_per_epoch = len(batch_idxs)
    parser, _, loss_fun, frac_err = make_nn_funs(layer_sizes,
                                                 L2_reg,
                                                 return_parser=True)
    N_weights = parser.N

    def indexed_loss_fun(w, idxs):
        return loss_fun(w, X=train_images[idxs], T=train_labels[idxs])

    log_alphas = np.full(N_iters, log_alpha_0)
    betas = np.full(N_iters, beta_0)
    npr.seed(2)
    V0 = npr.randn(N_weights) * velocity_scale
    #W0 = npr.randn(N_weights) * np.exp(log_param_scale)

    bindict = {
        k: np.linspace(-1, 1, N_bins) *
        np.exp(log_param_scale)  # Different cdf per layer.
        for k, v in parser.idxs_and_shapes.iteritems()
    }
    output = []
    for i in range(N_meta_iter):
        print "Meta iteration {0}".format(i)
        #X0, dX_dbins = bininvcdf(W_uniform, bins)
        X_uniform = npr.rand(
            N_weights)  # Weights are uniform passed through an inverse cdf.
        X0 = np.zeros(N_weights)
        dX_dbins = {}
        for k, cur_bins in bindict.iteritems():
            cur_slice, cur_shape = parser.idxs_and_shapes[k]
            cur_xs = X_uniform[cur_slice]
            cur_X0, cur_dX_dbins = bininvcdf(cur_xs, cur_bins)
            X0[cur_slice] = cur_X0
            dX_dbins[k] = cur_dX_dbins
        results = sgd(indexed_loss_fun,
                      batch_idxs,
                      N_iters,
                      X0,
                      V0,
                      np.exp(log_alphas),
                      betas,
                      record_learning_curve=True)
        dL_dx = results['d_x']

        learning_curve = results['learning_curve']
        output.append((learning_curve, bindict))

        # Update bins with one gradient step.
        for k, bins in bindict.iteritems():
            dL_dbins = np.dot(parser.get(dL_dx, k).flatten(), dX_dbins[k])
            bins = bins - dL_dbins * bin_stepsize
            bins[[0, -1]] = bins[[0, -1]] - dL_dbins[[0, 1]] * bin_stepsize
            bindict[k] = np.sort(bins)
        bindict = bindict.copy()

    return output