Loading and inference in TensorFlow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to load a saved TensorFlow model.

TensorFlow

import tensorflow as tf
model = tf.keras.models.[1]('my_model')

Drag options to blanks, or click blank then click option'

Acompile_model

Bsave_model

Cload_model

Dfit_model

Attempts:

3 left

💡 Hint

Common Mistakes

Using save_model instead of load_model

Trying to compile or fit the model during loading

The function load_model loads a saved TensorFlow model from disk.

2fill in blank

medium

Complete the code to make predictions using the loaded model.

TensorFlow

predictions = model.[1](input_data)

Drag options to blanks, or click blank then click option'

Atrain

Bfit

Cevaluate

Dpredict

Attempts:

3 left

💡 Hint

Common Mistakes

Using fit or train instead of predict

Using evaluate which returns loss and metrics

The predict method is used to get the model's output for new input data.

3fill in blank

hard

Fix the error in the code to load a model from the file 'model.h5'.

TensorFlow

model = tf.keras.models.load_model([1])

Drag options to blanks, or click blank then click option'

Amodel.h5

B"model.h5"

Cmodel

D'model'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the filename without quotes

Passing a variable name instead of a string

The file path must be a string, so it needs quotes around it.

4fill in blank

hard

Fill both blanks to create a dictionary of predictions for each input sample.

TensorFlow

results = {i: model.[1](sample) for i, sample in enumerate([2])}

Drag options to blanks, or click blank then click option'

Apredict

Binput_data

Cfit

Devaluate

Attempts:

3 left

💡 Hint

Common Mistakes

Using fit or evaluate instead of predict

Using wrong variable name for input data

Use predict to get predictions for each sample in input_data.

5fill in blank

hard

Fill all three blanks to load a model, make predictions, and print the results.

TensorFlow

model = tf.keras.models.[1]('saved_model')
preds = model.[2](test_data)
print([3])

Drag options to blanks, or click blank then click option'

Aload_model

Bpredict

Cpreds

Dfit

Attempts:

3 left

💡 Hint

Common Mistakes

Using fit instead of predict

Printing the wrong variable

Not using quotes for the model path

Load the model with load_model, predict with predict, and print the predictions stored in preds.

Practice

1. What is the main purpose of tf.keras.models.load_model() in TensorFlow?

easy

A. To visualize the model architecture

B. To load a previously saved model for inference or further training

C. To compile a model with loss and optimizer

D. To create a new model architecture from scratch

Solution

1. Step 1: Understand the function purpose

   tf.keras.models.load_model() is used to load a model that was saved earlier, including its architecture, weights, and optimizer state.

2. Step 2: Differentiate from other functions

   Creating a new model or compiling it are separate steps. Loading is specifically for retrieving a saved model.

3. Final Answer:

   To load a previously saved model for inference or further training -> Option B

4. Quick Check:

   Load saved model = load_model() [OK]

Hint: Load saved models with load_model() function [OK]

Common Mistakes:

• Confusing load_model() with model creation
• Thinking load_model() compiles the model
• Assuming load_model() only loads weights

2. Which of the following is the correct way to get predictions from a loaded TensorFlow model named model on input data new_data?

easy

A. predictions = model.predict(new_data)

B. predictions = model.fit(new_data)

C. predictions = model.evaluate(new_data)

D. predictions = model.compile(new_data)

Solution

1. Step 1: Identify the correct method for inference

   To get predictions from a model, the method predict() is used.

2. Step 2: Understand other methods

   fit() trains the model, evaluate() tests performance, and compile() sets up the model.

3. Final Answer:

   predictions = model.predict(new_data) -> Option A

4. Quick Check:

   Predict new data = model.predict() [OK]

Hint: Use model.predict() to get predictions [OK]

Common Mistakes:

• Using fit() instead of predict() for inference
• Calling evaluate() expecting predictions
• Trying to compile() during prediction

3. Given the following code, what will be the shape of predictions?

import tensorflow as tf
import numpy as np
model = tf.keras.Sequential([
  tf.keras.layers.Dense(3, input_shape=(4,))
])
model.compile(optimizer='adam', loss='mse')
input_data = np.array([[1, 2, 3, 4], [5, 6, 7, 8]])
predictions = model.predict(input_data)

medium

A. (3, 4)

B. (4, 3)

C. (2, 3)

D. (2, 4)

Solution

1. Step 1: Analyze input shape and batch size

   The input data has shape (2, 4) meaning 2 samples, each with 4 features.

2. Step 2: Determine output shape from model layer

   The Dense layer outputs 3 units per sample, so output shape is (2, 3).

3. Final Answer:

   (2, 3) -> Option C

4. Quick Check:

   Input batch 2, output units 3 = (2, 3) [OK]

Hint: Output shape = (batch_size, units in last layer) [OK]

Common Mistakes:

• Confusing input shape with output shape
• Mixing batch size and feature dimensions
• Assuming output shape matches input shape

4. You loaded a model with model = tf.keras.models.load_model('my_model') but get this error when calling model.predict(new_data): ValueError: Error when checking input: expected dense_input to have shape (4,) but got array with shape (3,). What is the likely cause?

medium

A. The input data shape does not match the model's expected input shape

B. The model was not compiled before prediction

C. The model file is corrupted

D. The predict() method was called without training the model

Solution

1. Step 1: Understand the error message

   The error says the model expects input shape (4,), but received (3,), meaning input data shape is wrong.

2. Step 2: Rule out other causes

   Model compilation is not required for prediction, corrupted files cause different errors, and training is not needed for predict().

3. Final Answer:

   The input data shape does not match the model's expected input shape -> Option A

4. Quick Check:

   Input shape mismatch = ValueError [OK]

Hint: Match input data shape to model input shape exactly [OK]

Common Mistakes:

• Ignoring input shape mismatch
• Thinking model must be compiled before predict
• Assuming predict requires training first

5. You have a saved TensorFlow model that expects input shape (None, 5). You want to predict on a single sample with 5 features stored in a list sample = [1, 2, 3, 4, 5]. Which code snippet correctly prepares the input and gets the prediction?

hard

A. input_data = np.array(sample)
prediction = model.predict(input_data)

B. input_data = np.array(sample).reshape(1, 1, 5)
prediction = model.predict(input_data)

C. input_data = np.array(sample).reshape(5, 1)
prediction = model.predict(input_data)

D. import numpy as np
input_data = np.array([sample])
prediction = model.predict(input_data)

Solution

1. Step 1: Understand model input shape

   The model expects input shape (None, 5), where None is batch size, so input must be 2D with shape (batch_size, 5).

2. Step 2: Prepare input data correctly

   Wrapping the sample list in another list creates shape (1, 5), which matches expected input.

3. Step 3: Check other options

   input_data = np.array(sample) prediction = model.predict(input_data) gives shape (5,), not 2D; input_data = np.array(sample).reshape(5, 1) prediction = model.predict(input_data) reshapes to (5,1) which is wrong; input_data = np.array(sample).reshape(1, 1, 5) prediction = model.predict(input_data) reshapes to (1,1,5) which is 3D and incorrect.

4. Final Answer:

   import numpy as np input_data = np.array([sample]) prediction = model.predict(input_data) -> Option D

5. Quick Check:

   Input shape (1,5) matches model input [OK]

Hint: Wrap single sample in list to add batch dimension [OK]

Common Mistakes:

• Passing 1D array instead of 2D batch input
• Incorrect reshaping causing wrong input dimensions
• Adding extra unnecessary dimensions