Memodifikasi fungsi loss

Pada latihan sebelumnya, Anda mendefinisikan fungsi loss tensorflow lalu mengevaluasinya sekali untuk sekelompok nilai aktual dan nilai prediksi. Pada latihan ini, Anda akan menghitung loss di dalam fungsi lain bernama loss_function(), yang terlebih dahulu menghasilkan nilai prediksi dari data dan variabel. Tujuannya adalah membangun sebuah fungsi atas variabel model yang dapat dilatih yang mengembalikan nilai loss. Anda kemudian dapat mengevaluasi fungsi ini berulang kali untuk berbagai nilai variabel hingga menemukan nilai minimumnya. Dalam praktiknya, Anda akan meneruskan fungsi ini ke sebuah optimizer di tensorflow. Perhatikan bahwa features dan targets telah didefinisikan dan tersedia. Selain itu, Variable, float32, dan keras juga tersedia.

Latihan ini adalah bagian dari kursus

Pendahuluan TensorFlow di Python

Petunjuk latihan

Definisikan sebuah variabel, scalar, dengan nilai awal 1.0 dan tipe float32.
Definisikan fungsi bernama loss_function(), yang menerima scalar, features, dan targets sebagai argumen dalam urutan tersebut.
Gunakan fungsi loss mean absolute error.

Latihan interaktif praktis

Cobalah latihan ini dengan menyelesaikan kode contoh berikut.

# Initialize a variable named scalar
scalar = ____(1.0, ____)

# Define the model
def model(scalar, features = features):
  	return scalar * features

# Define a loss function
def loss_function(____, features = features, targets = targets):
	# Compute the predicted values
	predictions = model(scalar, features)
    
	# Return the mean absolute error loss
	return keras.losses.____(targets, predictions)

# Evaluate the loss function and print the loss
print(loss_function(scalar).numpy())

Edit dan Jalankan Kode

Latihan ini adalah bagian dari kursus

Pendahuluan TensorFlow di Python

SkillTag.level.intermediateSkillTag.label

4.8+

Mulai Kursus Gratis

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: Constants and variables Exercise 2: Defining data as constants Exercise 3: Defining variables Exercise 4: Basic operations Exercise 5: Performing element-wise multiplication Exercise 6: Making predictions with matrix multiplication Exercise 7: Summing over tensor dimensions Exercise 8: Advanced operations Exercise 9: Reshaping tensors Exercise 10: Optimizing with gradients Exercise 11: Working with image data

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: Data masukan Exercise 2: Muat data menggunakan pandas Exercise 3: Menetapkan tipe data Exercise 4: Fungsi kerugian Exercise 5: Fungsi loss di TensorFlow Exercise 6: Memodifikasi fungsi loss

Latihan Saat Ini

Exercise 7: Regresi linear Exercise 8: Menyusun regresi linear Exercise 9: Latih model linear Exercise 10: Regresi linear berganda Exercise 11: Pelatihan batch Exercise 12: Mempersiapkan pelatihan batch Exercise 13: Melatih model linear secara batch

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!