FeatureSpace advanced use cases

Author: Dimitre Oliveira
Date created: 2023/07/01
Last modified: 2023/07/01
Description: How to use FeatureSpace for advanced preprocessing use cases.

View in Colab • GitHub source

Introduction

This example is an extension of the Structured data classification with FeatureSpace code example, and here we will extend it to cover more complex use cases of the [keras.utils.FeatureSpace](/api/utils/feature_space#featurespace-class) preprocessing utility, like feature hashing, feature crosses, handling missing values and integrating Keras preprocessing layers with FeatureSpace.

The general task still is structured data classification (also known as tabular data classification) using a data that includes numerical features, integer categorical features, and string categorical features.

The dataset

Our dataset is provided by a Portuguese banking institution. It's a CSV file with 4119 rows. Each row contains information about marketing campaigns based on phone calls, and each column describes an attribute of the client. We use the features to predict whether the client subscribed ('yes') or not ('no') to the product (bank term deposit).

Here's the description of each feature:

Important note regarding the feature duration: this attribute highly affects the output target (e.g., if duration=0 then y='no'). Yet, the duration is not known before a call is performed. Also, after the end of the call y is obviously known. Thus, this input should only be included for benchmark purposes and should be discarded if the intention is to have a realistic predictive model. For this reason we will drop it.

Setup

import pandas as pd
import tensorflow as tf
from pathlib import Path
from zipfile import ZipFile
from tensorflow.keras.utils import FeatureSpace

Load the data

Let's download the data and load it into a Pandas dataframe:

data_url = "https://archive.ics.uci.edu/static/public/222/bank+marketing.zip"
data_zipped_path = tf.keras.utils.get_file("bank_marketing.zip", data_url, extract=True)
keras_datasets_path = Path(data_zipped_path).parents[0]
with ZipFile(f"{keras_datasets_path}/bank-additional.zip", "r") as zip:
    # Extract files
    zip.extractall(path=keras_datasets_path)

dataframe = pd.read_csv(
    f"{keras_datasets_path}/bank-additional/bank-additional.csv", sep=";"
)

Downloading data from https://archive.ics.uci.edu/static/public/222/bank+marketing.zip
   8192/Unknown - 0s 0us/step

We will create a new feature previously_contacted to be able to demonstrate some useful preprocessing techniques, this feature is based on pdays. According to the dataset information if pdays = 999 it means that the client was not previously contacted, so let's create a feature to capture that.

# Droping `duration` to avoid target leak
dataframe.drop("duration", axis=1, inplace=True)
# Creating the new feature `previously_contacted`
dataframe["previously_contacted"] = dataframe["pdays"].map(
    lambda x: 0 if x == 999 else 1
)

The dataset includes 4119 samples with 21 columns per sample (20 features, plus the target label), here's a preview of a few samples:

print(f"Dataframe shape: {dataframe.shape}")
display(dataframe.head())

Dataframe shape: (4119, 21)

The column, "y", indicates whether the client has subscribed a term deposit or not.

Train/validation split

Let's split the data into a training and validation set:

valid_dataframe = dataframe.sample(frac=0.2, random_state=0)
train_dataframe = dataframe.drop(valid_dataframe.index)

print(
    f"Using {len(train_dataframe)} samples for training and "
    f"{len(valid_dataframe)} for validation"
)

Using 3295 samples for training and 824 for validation

Generating TF datasets

Let's generate [tf.data.Dataset](https://www.tensorflow.org/api_docs/python/tf/data/Dataset) objects for each dataframe, since our target column y is a string we also need to encode it as an integer to be able to train our model with it. To achieve this we will create a StringLookup layer that will map the strings "no" and "yes" into "0" and "1" respectively.

label_lookup = tf.keras.layers.StringLookup(
    # the order here is important since the first index will be encoded as 0
    vocabulary=["no", "yes"],
    num_oov_indices=0,
)


def encode_label(x, y):
    encoded_y = label_lookup(y)
    return x, encoded_y


def dataframe_to_dataset(dataframe):
    dataframe = dataframe.copy()
    labels = dataframe.pop("y")
    ds = tf.data.Dataset.from_tensor_slices((dict(dataframe), labels))
    ds = ds.map(encode_label, num_parallel_calls=tf.data.AUTOTUNE)
    ds = ds.shuffle(buffer_size=len(dataframe))
    return ds


train_ds = dataframe_to_dataset(train_dataframe)
valid_ds = dataframe_to_dataset(valid_dataframe)

/Users/dimitreoliveira/Desktop/keras-io/.venvs/dev/lib/python3.11/site-packages/numpy/core/numeric.py:2463: FutureWarning: elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison
  return bool(asarray(a1 == a2).all())

Each Dataset yields a tuple (input, target) where input is a dictionary of features and target is the value 0 or 1:

for x, y in dataframe_to_dataset(train_dataframe).take(1):
    print(f"Input: {x}")
    print(f"Target: {y}")

Input: {'age': <tf.Tensor: shape=(), dtype=int64, numpy=57>, 'job': <tf.Tensor: shape=(), dtype=string, numpy=b'housemaid'>, 'marital': <tf.Tensor: shape=(), dtype=string, numpy=b'married'>, 'education': <tf.Tensor: shape=(), dtype=string, numpy=b'basic.4y'>, 'default': <tf.Tensor: shape=(), dtype=string, numpy=b'no'>, 'housing': <tf.Tensor: shape=(), dtype=string, numpy=b'yes'>, 'loan': <tf.Tensor: shape=(), dtype=string, numpy=b'no'>, 'contact': <tf.Tensor: shape=(), dtype=string, numpy=b'telephone'>, 'month': <tf.Tensor: shape=(), dtype=string, numpy=b'jul'>, 'day_of_week': <tf.Tensor: shape=(), dtype=string, numpy=b'thu'>, 'campaign': <tf.Tensor: shape=(), dtype=int64, numpy=3>, 'pdays': <tf.Tensor: shape=(), dtype=int64, numpy=999>, 'previous': <tf.Tensor: shape=(), dtype=int64, numpy=0>, 'poutcome': <tf.Tensor: shape=(), dtype=string, numpy=b'nonexistent'>, 'emp.var.rate': <tf.Tensor: shape=(), dtype=float64, numpy=1.4>, 'cons.price.idx': <tf.Tensor: shape=(), dtype=float64, numpy=93.918>, 'cons.conf.idx': <tf.Tensor: shape=(), dtype=float64, numpy=-42.7>, 'euribor3m': <tf.Tensor: shape=(), dtype=float64, numpy=4.966>, 'nr.employed': <tf.Tensor: shape=(), dtype=float64, numpy=5228.1>, 'previously_contacted': <tf.Tensor: shape=(), dtype=int64, numpy=0>}
Target: 0

Preprocessing

Usually our data is not on the proper or best format for modeling, this is why most of the time we need to do some kind of preprocessing on the features to make them compatible with the model or to extract the most of them for the task. We need to do this preprocessing step for training but but at inference we also need to make sure that the data goes through the same process, this where a utility like FeatureSpace shines, we can define all the preprocessing once and re-use it at different stages of our system.

Here we will see how to use FeatureSpace to perform more complex transformations and its flexibility, then combine everything together into a single component to preprocess data for our model.

The FeatureSpace utility learns how to process the data by using the adapt() function to learn from it, this requires a dataset containing only feature, so let's create it together with a utility function to show the preprocessing example in practice:

train_ds_with_no_labels = train_ds.map(lambda x, _: x)


def example_feature_space(dataset, feature_space, feature_names):
    feature_space.adapt(dataset)
    for x in dataset.take(1):
        inputs = {feature_name: x[feature_name] for feature_name in feature_names}
        preprocessed_x = feature_space(inputs)
        print(f"Input: {[{k:v.numpy()} for k, v in inputs.items()]}")
        print(
            f"Preprocessed output: {[{k:v.numpy()} for k, v in preprocessed_x.items()]}"
        )

Feature hashing

Feature hashing means hashing or encoding a set of values into a defined number of bins, in this case we have campaign (number of contacts performed during this campaign and for a client) which is a numerical feature that can assume a varying range of values and we will hash it into 4 bins, this means that any possible value of the original feature will be placed into one of those possible 4 bins. The output here can be a one-hot encoded vector or a single number.

feature_space = FeatureSpace(
    features={
        "campaign": FeatureSpace.integer_hashed(num_bins=4, output_mode="one_hot")
    },
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["campaign"])

Input: [{'campaign': 1}]
Preprocessed output: [{'campaign': array([0., 1., 0., 0.], dtype=float32)}]

Feature hashing can also be used for string features.

feature_space = FeatureSpace(
    features={
        "education": FeatureSpace.string_hashed(num_bins=3, output_mode="one_hot")
    },
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["education"])

Input: [{'education': b'high.school'}]
Preprocessed output: [{'education': array([1., 0., 0.], dtype=float32)}]

For numerical features we can get a similar behavior by using the float_discretized option, the main difference between this and integer_hashed is that with the former we bin the values while keeping some numerical relationship (close values will likely be placed at the same bin) while the later (hashing) we cannot guarantee that those numbers will be hashed into the same bin, it depends on the hashing function.

feature_space = FeatureSpace(
    features={"age": FeatureSpace.float_discretized(num_bins=3, output_mode="one_hot")},
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["age"])

Input: [{'age': 36}]
Preprocessed output: [{'age': array([0., 1., 0.], dtype=float32)}]

Feature indexing

Indexing a string feature essentially means creating a discrete numerical representation for it, this is especially important for string features since most models only accept numerical features. This transformation will place the string values into different categories. The output here can be a one-hot encoded vector or a single number.

Note that by specifying num_oov_indices=1 we leave one spot at our output vector for OOV (out of vocabulary) values this is an important tool to handle missing or unseen values after the training (values that were not seen during the adapt() step)

feature_space = FeatureSpace(
    features={
        "default": FeatureSpace.string_categorical(
            num_oov_indices=1, output_mode="one_hot"
        )
    },
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["default"])

Input: [{'default': b'unknown'}]
Preprocessed output: [{'default': array([0., 0., 1., 0.], dtype=float32)}]

We also can do feature indexing for integer features, this can be quite important for some datasets where categorical features are replaced by numbers, for instance features like sex or gender where values like (1 and 0) do not have a numerical relationship between them, they are just different categories, this behavior can be perfectly captured by this transformation.

On this dataset we can use the feature that we created previously_contacted. For this case we want to explicitly set num_oov_indices=0, the reason is that we only expect two possible values for the feature, anything else would be either wrong input or an issue with the data creation, for this reason we would probably just want the code to throw an error so that we can be aware of the issue and fix it.

feature_space = FeatureSpace(
    features={
        "previously_contacted": FeatureSpace.integer_categorical(
            num_oov_indices=0, output_mode="one_hot"
        )
    },
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["previously_contacted"])

Input: [{'previously_contacted': 0}]
Preprocessed output: [{'previously_contacted': array([1., 0.], dtype=float32)}]

Feature crosses (mixing features of diverse types)

With crosses we can do feature interactions between an arbitrary number of features of mixed types as long as they are categorical features, you can think of instead of having a feature {'age': 20} and another {'job': 'entrepreneur'} we can have {'age_X_job': 20_entrepreneur}, but with FeatureSpace and crosses we can apply specific preprocessing to each individual feature and to the feature cross itself. This option can be very powerful for specific use cases, here might be a good option since age combined with job can have different meanings for the banking domain.

We will cross age and job and hash the combination output of them into a vector representation of size 8. The output here can be a one-hot encoded vector or a single number.

Sometimes the combination of multiple features can result into on a super large feature space, think about crossing someone's ZIP code with its last name, the possibilities would be in the thousands, that is why the crossing_dim parameter is so important it limits the output dimension of the cross feature.

Note that the combination of possible values of the 6 bins of age and the 12 values of job would be 72, so by choosing crossing_dim = 8 we are choosing to constrain the output vector.

feature_space = FeatureSpace(
    features={
        "age": FeatureSpace.integer_hashed(num_bins=6, output_mode="one_hot"),
        "job": FeatureSpace.string_categorical(
            num_oov_indices=0, output_mode="one_hot"
        ),
    },
    crosses=[
        FeatureSpace.cross(
            feature_names=("age", "job"),
            crossing_dim=8,
            output_mode="one_hot",
        )
    ],
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["age", "job"])

Input: [{'age': 43}, {'job': b'management'}]
Preprocessed output: [{'age': array([1., 0., 0., 0., 0., 0.], dtype=float32)}, {'job': array([0., 0., 0., 0., 1., 0., 0., 0., 0., 0., 0., 0.], dtype=float32)}, {'age_X_job': array([0., 0., 0., 0., 0., 0., 1., 0.], dtype=float32)}]

FeatureSpace using a Keras preprocessing layer

To be a really flexible and extensible feature we cannot only rely on those pre-defined transformation, we must be able to re-use other transformations from the Keras/TensorFlow ecosystem and customize our own, this is why FeatureSpace is also designed to work with Keras preprocessing layers, this way we can use sophisticated data transformations provided by the framework, you can even create your own custom Keras preprocessing layers and use it in the same way.

Here we are going to use the [tf.keras.layers.TextVectorization](/api/layers/preprocessing_layers/text/text_vectorization#textvectorization-class) preprocessing layer to create a TF-IDF feature from our data. Note that this feature is not a really good use case for TF-IDF, this is just for demonstration purposes.

custom_layer = tf.keras.layers.TextVectorization(output_mode="tf_idf")

feature_space = FeatureSpace(
    features={
        "education": FeatureSpace.feature(
            preprocessor=custom_layer, dtype="string", output_mode="float"
        )
    },
    output_mode="dict",
)
example_feature_space(train_ds_with_no_labels, feature_space, ["education"])

Input: [{'education': b'high.school'}]
Preprocessed output: [{'education': array([0.       , 0.       , 1.6840783, 0.       , 0.       , 0.       ,
       0.       , 0.       , 0.       ], dtype=float32)}]

Configuring the final FeatureSpace

Now that we know how to use FeatureSpace for more complex use cases let's pick the ones that looks more useful for this task and create the final FeatureSpace component.

To configure how each feature should be preprocessed, we instantiate a keras.utils.FeatureSpace, and we pass to it a dictionary that maps the name of our features to the feature transformation function.

feature_space = FeatureSpace(
    features={
        # Categorical features encoded as integers
        "previously_contacted": FeatureSpace.integer_categorical(num_oov_indices=0),
        # Categorical features encoded as string
        "marital": FeatureSpace.string_categorical(num_oov_indices=0),
        "education": FeatureSpace.string_categorical(num_oov_indices=0),
        "default": FeatureSpace.string_categorical(num_oov_indices=0),
        "housing": FeatureSpace.string_categorical(num_oov_indices=0),
        "loan": FeatureSpace.string_categorical(num_oov_indices=0),
        "contact": FeatureSpace.string_categorical(num_oov_indices=0),
        "month": FeatureSpace.string_categorical(num_oov_indices=0),
        "day_of_week": FeatureSpace.string_categorical(num_oov_indices=0),
        "poutcome": FeatureSpace.string_categorical(num_oov_indices=0),
        # Categorical features to hash and bin
        "job": FeatureSpace.string_hashed(num_bins=3),
        # Numerical features to hash and bin
        "pdays": FeatureSpace.integer_hashed(num_bins=4),
        # Numerical features to normalize and bin
        "age": FeatureSpace.float_discretized(num_bins=4),
        # Numerical features to normalize
        "campaign": FeatureSpace.float_normalized(),
        "previous": FeatureSpace.float_normalized(),
        "emp.var.rate": FeatureSpace.float_normalized(),
        "cons.price.idx": FeatureSpace.float_normalized(),
        "cons.conf.idx": FeatureSpace.float_normalized(),
        "euribor3m": FeatureSpace.float_normalized(),
        "nr.employed": FeatureSpace.float_normalized(),
    },
    # Specify feature cross with a custom crossing dim.
    crosses=[
        FeatureSpace.cross(feature_names=("age", "job"), crossing_dim=8),
        FeatureSpace.cross(
            feature_names=("default", "housing", "loan"), crossing_dim=6
        ),
        FeatureSpace.cross(
            feature_names=("poutcome", "previously_contacted"), crossing_dim=2
        ),
    ],
    output_mode="concat",
)

Adapt the FeatureSpace to the training data

Before we start using the FeatureSpace to build a model, we have to adapt it to the training data. During adapt(), the FeatureSpace will:

• Index the set of possible values for categorical features.
• Compute the mean and variance for numerical features to normalize.
• Compute the value boundaries for the different bins for numerical features to discretize.
• Any other kind of preprocessing required by custom layers.

Note that adapt() should be called on a tf.data.Dataset which yields dicts of feature values – no labels.

But first let's batch the datasets

train_ds = train_ds.batch(32)
valid_ds = valid_ds.batch(32)

train_ds_with_no_labels = train_ds.map(lambda x, _: x)
feature_space.adapt(train_ds_with_no_labels)

At this point, the FeatureSpace can be called on a dict of raw feature values, and because we set output_mode="concat" it will return a single concatenate vector for each sample, combining encoded features and feature crosses.

for x, _ in train_ds.take(1):
    preprocessed_x = feature_space(x)
    print(f"preprocessed_x shape: {preprocessed_x.shape}")
    print(f"preprocessed_x sample: \n{preprocessed_x[0]}")

preprocessed_x shape: (32, 77)
preprocessed_x sample: 
[ 0.          0.          1.          0.         -0.58789116 -0.47766402
  0.59354883  1.          0.          1.          0.          0.
  0.          0.          1.          0.          0.          0.
  0.          0.          1.          0.          0.          0.
  0.          0.8486566   0.77920455  1.          0.          0.
  0.          1.          0.          0.          1.          0.
  1.          0.          0.          0.          0.          1.
  0.          0.          0.          0.          0.          0.
  0.          0.          0.84002995  0.          0.          1.
  0.          1.          0.          0.         -0.35691866  1.
  0.          0.          0.          0.          0.          1.
  0.          0.          0.          0.          1.          0.
  0.          0.          0.          1.          0.        ]

Saving the FeatureSpace

At this point we can choose to save our FeatureSpace component, this have many advantages like re-using it on different experiments that use the same model, saving time if you need to re-run the preprocessing step, and mainly for model deployment, where by loading it you can be sure that you will be applying the same preprocessing steps don't matter the device or environment, this is a great way to reduce training/servingskew.

feature_space.save("myfeaturespace.keras")

Preprocessing with FeatureSpace as part of the tf.data pipeline

We will opt to use our component asynchronously by making it part of the tf.data pipeline, as noted at the previous guide This enables asynchronous parallel preprocessing of the data on CPU before it hits the model. Usually, this is always the right thing to do during training.

Let's create a training and validation dataset of preprocessed batches:

preprocessed_train_ds = train_ds.map(
    lambda x, y: (feature_space(x), y), num_parallel_calls=tf.data.AUTOTUNE
).prefetch(tf.data.AUTOTUNE)

preprocessed_valid_ds = valid_ds.map(
    lambda x, y: (feature_space(x), y), num_parallel_calls=tf.data.AUTOTUNE
).prefetch(tf.data.AUTOTUNE)

Model

We will take advantage of our FeatureSpace component to build the model, as we want the model to be compatible with our preprocessing function, let's use the the FeatureSpace feature map as the input of our model.

encoded_features = feature_space.get_encoded_features()
print(encoded_features)

KerasTensor(type_spec=TensorSpec(shape=(None, 77), dtype=tf.float32, name=None), name='concatenate/concat:0', description="created by layer 'concatenate'")

This model is quite trivial only for demonstration purposes so don't pay too much attention to the architecture.

x = tf.keras.layers.Dense(64, activation="relu")(encoded_features)
x = tf.keras.layers.Dropout(0.5)(x)
output = tf.keras.layers.Dense(1, activation="sigmoid")(x)

model = tf.keras.Model(inputs=encoded_features, outputs=output)
model.compile(optimizer="adam", loss="binary_crossentropy", metrics=["accuracy"])

Training

Let's train our model for 20 epochs. Note that feature preprocessing is happening as part of the tf.data pipeline, not as part of the model.

model.fit(
    preprocessed_train_ds, validation_data=preprocessed_valid_ds, epochs=20, verbose=2
)

Epoch 1/20
103/103 - 2s - loss: 0.3399 - accuracy: 0.8777 - val_loss: 0.2653 - val_accuracy: 0.9114 - 2s/epoch - 23ms/step
Epoch 2/20
103/103 - 1s - loss: 0.3077 - accuracy: 0.8953 - val_loss: 0.2650 - val_accuracy: 0.9114 - 848ms/epoch - 8ms/step
Epoch 3/20
103/103 - 1s - loss: 0.3001 - accuracy: 0.8956 - val_loss: 0.2638 - val_accuracy: 0.9114 - 852ms/epoch - 8ms/step
Epoch 4/20
103/103 - 1s - loss: 0.2942 - accuracy: 0.8950 - val_loss: 0.2679 - val_accuracy: 0.9029 - 842ms/epoch - 8ms/step
Epoch 5/20
103/103 - 1s - loss: 0.2897 - accuracy: 0.8995 - val_loss: 0.2649 - val_accuracy: 0.9078 - 845ms/epoch - 8ms/step
Epoch 6/20
103/103 - 1s - loss: 0.2893 - accuracy: 0.8992 - val_loss: 0.2648 - val_accuracy: 0.9078 - 844ms/epoch - 8ms/step
Epoch 7/20
103/103 - 1s - loss: 0.2869 - accuracy: 0.8980 - val_loss: 0.2649 - val_accuracy: 0.9090 - 836ms/epoch - 8ms/step
Epoch 8/20
103/103 - 1s - loss: 0.2892 - accuracy: 0.8953 - val_loss: 0.2647 - val_accuracy: 0.9066 - 832ms/epoch - 8ms/step
Epoch 9/20
103/103 - 1s - loss: 0.2856 - accuracy: 0.9011 - val_loss: 0.2641 - val_accuracy: 0.9102 - 831ms/epoch - 8ms/step
Epoch 10/20
103/103 - 1s - loss: 0.2810 - accuracy: 0.8998 - val_loss: 0.2647 - val_accuracy: 0.9090 - 840ms/epoch - 8ms/step
Epoch 11/20
103/103 - 1s - loss: 0.2841 - accuracy: 0.8980 - val_loss: 0.2659 - val_accuracy: 0.9041 - 830ms/epoch - 8ms/step
Epoch 12/20
103/103 - 1s - loss: 0.2828 - accuracy: 0.8983 - val_loss: 0.2652 - val_accuracy: 0.9053 - 833ms/epoch - 8ms/step
Epoch 13/20
103/103 - 1s - loss: 0.2815 - accuracy: 0.9023 - val_loss: 0.2639 - val_accuracy: 0.9126 - 834ms/epoch - 8ms/step
Epoch 14/20
103/103 - 1s - loss: 0.2830 - accuracy: 0.8953 - val_loss: 0.2659 - val_accuracy: 0.9053 - 835ms/epoch - 8ms/step
Epoch 15/20
103/103 - 1s - loss: 0.2848 - accuracy: 0.8977 - val_loss: 0.2637 - val_accuracy: 0.9090 - 831ms/epoch - 8ms/step
Epoch 16/20
103/103 - 1s - loss: 0.2764 - accuracy: 0.8986 - val_loss: 0.2653 - val_accuracy: 0.9053 - 829ms/epoch - 8ms/step
Epoch 17/20
103/103 - 1s - loss: 0.2813 - accuracy: 0.8995 - val_loss: 0.2635 - val_accuracy: 0.9078 - 826ms/epoch - 8ms/step
Epoch 18/20
103/103 - 1s - loss: 0.2790 - accuracy: 0.9023 - val_loss: 0.2677 - val_accuracy: 0.9017 - 831ms/epoch - 8ms/step
Epoch 19/20
103/103 - 1s - loss: 0.2820 - accuracy: 0.8968 - val_loss: 0.2644 - val_accuracy: 0.9066 - 835ms/epoch - 8ms/step
Epoch 20/20
103/103 - 1s - loss: 0.2812 - accuracy: 0.9002 - val_loss: 0.2661 - val_accuracy: 0.9029 - 898ms/epoch - 9ms/step

<keras.callbacks.History at 0x2d2ff5090>

Inference on new data with the end-to-end model

Now, we can build our inference model (which includes the FeatureSpace) to make predictions based on dicts of raw features values, as follows:

Loading the FeatureSpace

First let's load the FeatureSpace that we saved a few moment ago, this can be quite handy if you train a model but want to do inference at different time, possibly using a different device or environment.

loaded_feature_space = tf.keras.models.load_model("myfeaturespace.keras")

/Users/dimitreoliveira/Desktop/keras-io/.venvs/dev/lib/python3.11/site-packages/numpy/core/numeric.py:2463: FutureWarning: elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison
  return bool(asarray(a1 == a2).all())

Building the inference end-to-end model

To build the inference model we need both the feature input map and the preprocessing encoded Keras tensors.

dict_inputs = loaded_feature_space.get_inputs()
encoded_features = loaded_feature_space.get_encoded_features()
print(encoded_features)

print(dict_inputs)

outputs = model(encoded_features)
inference_model = tf.keras.Model(inputs=dict_inputs, outputs=outputs)

sample = {
    "age": 30,
    "job": "blue-collar",
    "marital": "married",
    "education": "basic.9y",
    "default": "no",
    "housing": "yes",
    "loan": "no",
    "contact": "cellular",
    "month": "may",
    "day_of_week": "fri",
    "campaign": 2,
    "pdays": 999,
    "previous": 0,
    "poutcome": "nonexistent",
    "emp.var.rate": -1.8,
    "cons.price.idx": 92.893,
    "cons.conf.idx": -46.2,
    "euribor3m": 1.313,
    "nr.employed": 5099.1,
    "previously_contacted": 0,
}

input_dict = {name: tf.convert_to_tensor([value]) for name, value in sample.items()}
predictions = inference_model.predict(input_dict)

print(
    f"This particular client has a {100 * predictions[0][0]:.2f}% probability "
    "of subscribing a term deposit, as evaluated by our model."
)

KerasTensor(type_spec=TensorSpec(shape=(None, 77), dtype=tf.float32, name=None), name='concatenate_1/concat:0', description="created by layer 'concatenate_1'")
{'previously_contacted': <KerasTensor: shape=(None, 1) dtype=int64 (created by layer 'previously_contacted')>, 'marital': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'marital')>, 'education': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'education')>, 'default': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'default')>, 'housing': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'housing')>, 'loan': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'loan')>, 'contact': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'contact')>, 'month': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'month')>, 'day_of_week': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'day_of_week')>, 'poutcome': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'poutcome')>, 'job': <KerasTensor: shape=(None, 1) dtype=string (created by layer 'job')>, 'pdays': <KerasTensor: shape=(None, 1) dtype=int64 (created by layer 'pdays')>, 'age': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'age')>, 'campaign': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'campaign')>, 'previous': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'previous')>, 'emp.var.rate': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'emp.var.rate')>, 'cons.price.idx': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'cons.price.idx')>, 'cons.conf.idx': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'cons.conf.idx')>, 'euribor3m': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'euribor3m')>, 'nr.employed': <KerasTensor: shape=(None, 1) dtype=float32 (created by layer 'nr.employed')>}
1/1 [==============================] - 1s 568ms/step
This particular client has a 8.59% probability of subscribing a term deposit, as evaluated by our model.