Modern syntax for old-fashioned Keras command "Convolution2D"? - tensorflow

Question

I was studying different CNN architectures to predict the CIFAR10 dataset, and I found this interesting Github repository:
https://gist.github.com/wielandbrendel/ccf1ff6f8f92139439be
I tried to run the model, but it was created in 6 years ago and the following Keras command is no longer valid:
model.add(Convolution2D(32, 3, 3, 3, border_mode='full'))
How is this command translated into the modern Keras syntax for Conv2D?
I get an error in Keras when I try to input the sequence of integers in Convolution2D(32, 3, 3, 3, ...)?
I guess 32 is the number of channels, and then we specify a 3x3 kernel size, but I am not sure about the meaning of the last 3 mentioned (4th position).
PS. Changing border_mode into padding = 'valid' or 'same' returns the following error:
model.add(Convolution2D(32, 3, 3, 3, padding='valid'))
TypeError: __init__() got multiple values for argument 'padding'

Answer 1

The gist there you're following is backdated and also has some issues. You don't need to follow this now. Here is the updated version of it. Try this.
Imports and DataSet
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import (Dense, Dropout, Activation,
Flatten, Conv2D, MaxPooling2D)
from tensorflow.keras.optimizers import SGD, Adadelta, Adagrad
import tensorflow as tf
# parameters
batch_size = 32
nb_classes = 10
nb_epoch = 5
# the data, shuffled and split between tran and test sets
(X_train, y_train), (X_test, y_test) = tf.keras.datasets.cifar10.load_data()
# convert class vectors to binary class matrices
Y_train = tf.keras.utils.to_categorical(y_train, nb_classes)
Y_test = tf.keras.utils.to_categorical(y_test, nb_classes)
# train model
X_train = X_train.astype("float32") / 255
X_test = X_test.astype("float32") / 255
X_train.shape, y_train.shape, X_test.shape, y_test.shape
((50000, 32, 32, 3), (50000, 1), (10000, 32, 32, 3), (10000, 1))
Modeling
model = Sequential()
model.add(Conv2D(filters=32, kernel_size=(3, 3),
strides=(1, 1), activation='relu', padding="same"))
model.add(Activation('relu'))
model.add(Conv2D(filters=32, kernel_size=(3, 3),
strides=(1, 1), activation='relu', padding="same"))
model.add(Activation('relu'))
model.add(MaxPooling2D((2, 2)))
model.add(Dropout(0.25))
model.add(Conv2D(filters=32, kernel_size=(3, 3),
strides=(1, 1), activation='relu', padding="same"))
model.add(Activation('relu'))
model.add(Conv2D(filters=32, kernel_size=(3, 3),
strides=(1, 1), activation='relu', padding="same"))
model.add(Activation('relu'))
model.add(MaxPooling2D((2, 2)))
model.add(Dropout(0.25))
model.add(Flatten())
model.add(Dense(512))
model.add(Activation('relu'))
model.add(Dropout(0.5))
model.add(Dense(nb_classes))
model.add(Activation('softmax'))
# let's train the model using SGD + momentum (how original).
sgd = SGD(lr=0.01, decay=1e-6, momentum=0.9, nesterov=True)
model.compile(loss='categorical_crossentropy', optimizer=sgd, metrics=['accuracy'])
Compile and Run
model.fit(X_train, Y_train, batch_size=batch_size, epochs=nb_epoch)
# test score & top 1 performance
score = model.evaluate(X_test, Y_test, batch_size=batch_size)
y_hat = model.predict(X_test)
yhat = np.argmax(y_hat, 1)
top1 = np.mean(yhat == np.squeeze(y_test))
print('Test score/Top1', score, top1)

Answer 2

The Convolutional2D is now named Conv2D, but there is still an alias for Convolutional2D, so that's not a problem.
The border_mode argument is not available anymore, the equivalent is padding, with options valid or same.
Try both to see if any of those fits the shapes of the outputs and allows to code to work.