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@fchollet
Last active May 15, 2024 07:19
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Updated to the Keras 2.0 API.
'''This script goes along the blog post
"Building powerful image classification models using very little data"
from blog.keras.io.
It uses data that can be downloaded at:
https://www.kaggle.com/c/dogs-vs-cats/data
In our setup, we:
- created a data/ folder
- created train/ and validation/ subfolders inside data/
- created cats/ and dogs/ subfolders inside train/ and validation/
- put the cat pictures index 0-999 in data/train/cats
- put the cat pictures index 1000-1400 in data/validation/cats
- put the dogs pictures index 12500-13499 in data/train/dogs
- put the dog pictures index 13500-13900 in data/validation/dogs
So that we have 1000 training examples for each class, and 400 validation examples for each class.
In summary, this is our directory structure:
```
data/
train/
dogs/
dog001.jpg
dog002.jpg
...
cats/
cat001.jpg
cat002.jpg
...
validation/
dogs/
dog001.jpg
dog002.jpg
...
cats/
cat001.jpg
cat002.jpg
...
```
'''
from keras.preprocessing.image import ImageDataGenerator
from keras.models import Sequential
from keras.layers import Conv2D, MaxPooling2D
from keras.layers import Activation, Dropout, Flatten, Dense
from keras import backend as K
# dimensions of our images.
img_width, img_height = 150, 150
train_data_dir = 'data/train'
validation_data_dir = 'data/validation'
nb_train_samples = 2000
nb_validation_samples = 800
epochs = 50
batch_size = 16
if K.image_data_format() == 'channels_first':
input_shape = (3, img_width, img_height)
else:
input_shape = (img_width, img_height, 3)
model = Sequential()
model.add(Conv2D(32, (3, 3), input_shape=input_shape))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Conv2D(32, (3, 3)))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Conv2D(64, (3, 3)))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Flatten())
model.add(Dense(64))
model.add(Activation('relu'))
model.add(Dropout(0.5))
model.add(Dense(1))
model.add(Activation('sigmoid'))
model.compile(loss='binary_crossentropy',
optimizer='rmsprop',
metrics=['accuracy'])
# this is the augmentation configuration we will use for training
train_datagen = ImageDataGenerator(
rescale=1. / 255,
shear_range=0.2,
zoom_range=0.2,
horizontal_flip=True)
# this is the augmentation configuration we will use for testing:
# only rescaling
test_datagen = ImageDataGenerator(rescale=1. / 255)
train_generator = train_datagen.flow_from_directory(
train_data_dir,
target_size=(img_width, img_height),
batch_size=batch_size,
class_mode='binary')
validation_generator = test_datagen.flow_from_directory(
validation_data_dir,
target_size=(img_width, img_height),
batch_size=batch_size,
class_mode='binary')
model.fit_generator(
train_generator,
steps_per_epoch=nb_train_samples // batch_size,
epochs=epochs,
validation_data=validation_generator,
validation_steps=nb_validation_samples // batch_size)
model.save_weights('first_try.h5')
@CESI2Jaafar
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I got this error, please give a bit detail how to solve this problem:
Found 0 images belonging to 0 classes.
Found 0 images belonging to 0 classes.
:70: UserWarning: Model.fit_generator is deprecated and will be removed in a future version. Please use Model.fit, which supports generators.
model.fit_generator(

ValueError Traceback (most recent call last)
in <cell line: 70>()
68 class_mode='binary')
69
---> 70 model.fit_generator(
71 train_generator,
72 steps_per_epoch=nb_train_samples // batch_size,

2 frames
/usr/local/lib/python3.9/dist-packages/keras/preprocessing/image.py in getitem(self, idx)
101 def getitem(self, idx):
102 if idx >= len(self):
--> 103 raise ValueError(
104 "Asked to retrieve element {idx}, "
105 "but the Sequence "

ValueError: Asked to retrieve element 0, but the Sequence has length 0

@CESI2Jaafar
Copy link

RuntimeError Traceback (most recent call last)
in <cell line: 54>()
52 model = Sequential()
53
---> 54 model.fit(
55 train_generator,
56 steps_per_epoch=2000,

1 frames
/usr/local/lib/python3.9/dist-packages/keras/engine/training.py in _assert_compile_was_called(self)
3683 # (i.e. whether the model is built and its inputs/outputs are set).
3684 if not self._is_compiled:
-> 3685 raise RuntimeError(
3686 "You must compile your model before "
3687 "training/testing. "

RuntimeError: You must compile your model before training/testing. Use model.compile(optimizer, loss).

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