Tensors umformen

Später im Kurs wirst du Bilder von Gebärdensprache-Buchstaben mit einem neuronalen Netz klassifizieren. In manchen Fällen erwartet das Netz 1‑dimensionale Tensoren als Eingaben, deine Daten liegen aber als Bilder vor – also als 2‑ oder 3‑dimensionale Tensoren, je nachdem, ob es Graustufen- oder Farbbilder sind.

Die Abbildung unten zeigt Graustufen- und Farbbilder des Gebärdensprache-Buchstabens A. Beide Bilder wurden bereits für dich importiert und in die numpy-Arrays gray_tensor und color_tensor umgewandelt. Forme diese Arrays mit der Operation reshape (aus tensorflow importiert) in 1‑dimensionale Vektoren um. Beachte: Die Form von gray_tensor ist 28x28 und die Form von color_tensor ist 28x28x3.

This figure shows grayscale and color images of the sign language letter "A".

Diese Übung ist Teil des Kurses

<Kurs>Einführung in TensorFlow mit Python</Kurs>

Übungsanweisungen

Forme gray_tensor von einer 28x28‑Matrix in einen 784x1‑Vektor mit dem Namen gray_vector um.
Forme color_tensor von einem 28x28x3‑Tensor in einen 2352x1‑Vektor mit dem Namen color_vector um.

Interaktive praktische Übung

Versuche dich an dieser Übung, indem du diesen Beispielcode vervollständigst.

# Reshape the grayscale image tensor into a vector
gray_vector = reshape(____, (____, 1))

# Reshape the color image tensor into a vector
color_vector = reshape(____, (____, ____))

Code bearbeiten und ausführen

Diese Übung ist Teil des Kurses

<Kurs>Einführung in TensorFlow mit Python</Kurs>

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Before you can build advanced models in TensorFlow 2, you will first need to understand the basics. In this chapter, you’ll learn how to define constants and variables, perform tensor addition and multiplication, and compute derivatives. Knowledge of linear algebra will be helpful, but not necessary.

Exercise 1: Konstanten und Variablen Exercise 2: Daten als Konstanten definieren Exercise 3: Variablen definieren Exercise 4: Grundlegende Operationen Exercise 5: Elementweise Multiplikation durchführen Exercise 6: Vorhersagen mit Matrixmultiplikation Exercise 7: Über Tensor-Dimensionen summieren Exercise 8: Fortgeschrittene Operationen Exercise 9: Tensors umformen

Aktuelle Übung

Exercise 10: Mit Gradienten optimieren Exercise 11: Mit Bilddaten arbeiten

In this chapter, you will learn how to build, solve, and make predictions with models in TensorFlow 2. You will focus on a simple class of models – the linear regression model – and will try to predict housing prices. By the end of the chapter, you will know how to load and manipulate data, construct loss functions, perform minimization, make predictions, and reduce resource use with batch training.

Exercise 1: Input data Exercise 2: Load data using pandas Exercise 3: Setting the data type Exercise 4: Loss functions Exercise 5: Loss functions in TensorFlow Exercise 6: Modifying the loss function Exercise 7: Linear regression Exercise 8: Set up a linear regression Exercise 9: Train a linear model Exercise 10: Multiple linear regression Exercise 11: Batch training Exercise 12: Preparing to batch train Exercise 13: Training a linear model in batches

The previous chapters taught you how to build models in TensorFlow 2. In this chapter, you will apply those same tools to build, train, and make predictions with neural networks. You will learn how to define dense layers, apply activation functions, select an optimizer, and apply regularization to reduce overfitting. You will take advantage of TensorFlow's flexibility by using both low-level linear algebra and high-level Keras API operations to define and train models.

Exercise 1: Dense layers Exercise 2: The linear algebra of dense layers Exercise 3: The low-level approach with multiple examples Exercise 4: Using the dense layer operation Exercise 5: Activation functions Exercise 6: Binary classification problems Exercise 7: Multiclass classification problems Exercise 8: Optimizers Exercise 9: The dangers of local minima Exercise 10: Avoiding local minima Exercise 11: Training a network in TensorFlow Exercise 12: Initialization in TensorFlow Exercise 13: Defining the model and loss function Exercise 14: Training neural networks with TensorFlow

In the final chapter, you'll use high-level APIs in TensorFlow 2 to train a sign language letter classifier. You will use both the sequential and functional Keras APIs to train, validate, make predictions with, and evaluate models. You will also learn how to use the Estimators API to streamline the model definition and training process, and to avoid errors.

Exercise 1: Defining neural networks with Keras Exercise 2: The sequential model in Keras Exercise 3: Compiling a sequential model Exercise 4: Defining a multiple input model Exercise 5: Training and validation with Keras Exercise 6: Training with Keras Exercise 7: Metrics and validation with Keras Exercise 8: Overfitting detection Exercise 9: Evaluating models Exercise 10: Training models with the Estimators API Exercise 11: Preparing to train with Estimators Exercise 12: Defining Estimators Exercise 13: Congratulations!