一维 CNN (Keras) 的输入形状

Question

I'm building a CNN using Keras, with the following Conv1D as my first layer:

cnn.add(Conv1D(
    filters=512,
    kernel_size=3,
    strides=2,
    activation=hyperparameters["activation_fn"],
    kernel_regularizer=getattr(regularizers, hyperparameters["regularization"])(hyperparameters["regularization_rate"]),
    input_shape=(1000, 1),
))

I'm training with the function:

cnn.fit(
    x=train_df["payload"].tolist(),
    y=train_df["label"].tolist(),
    batch_size=hyperparameters["batch_size"],
    epochs=hyperparameters["epochs"],
)

In which train_df is a pandas dataframe of two columns where, for each row, label is an int (0 or 1) and payload is a ndarray of floats padded with zeros/truncated to a length of 1000. The total # of training examples within train_df is 15641.

The model compiles, but during training, I get this error:

ValueError: Error when checking model input: the list of Numpy arrays that you are passing to your model is not the size the model expected. Expected to see 1 array(s), but instead got the following list of 15641 arrays: [array([[0.09019608],
   [0.01176471],
   [0.01176471],
   [0.        ],
   [0.30196078],
   [0.        ],
   [0.        ],
   [0.        ],
   [0.        ],
   [0....

I looked at this post and tried changing my input to a ndarray of 1000-float-long lists, but ended up with another error:

ValueError: Error when checking input: expected conv1d_1_input to have 3 dimensions, but got array with shape (15641, 1000)

Any ideas?

Answer 1

So I set the input_shape to (1000, 1)

I also converted the input that's fed to fit() into a single ndarray of n ndarrays (each ndarray is a vector of 1000 floats, n is the total count of samples/vectors) and reshaped each of those ndarrays to (1, 1000, 1) during preprocessing after reading this explanation on inputs & input shape

The final shape of my input data was (15641, 1000, 1)

All of this should apply to validation data too (if specified).

This fixed my issue