Failed to Convert NumPy Array to Tensor

When encountering the error "Failed to convert a NumPy array to a Tensor (Unsupported object type float)", it's important to identify potential causes related to data preparation and model definition.

Data Preparation

TensorFlow expects input data to be in a specific format. In this case, for LSTM models, the data should have the dimensions of (num_samples, timesteps, channels). Ensure that your training data, x_train, is formatted correctly. Converting your data to a NumPy array using x_array = np.asarray(x_list) and checking its shape can help verify its dimensions.

Furthermore, make sure that your data is properly preprocessed. Handle any categorical variables, missing values (NaNs), or strings appropriately.

Model Definition

Verify that your LSTM model is defined correctly. The input shape of the first LSTM layer should match the shape of your input data, which you can determine using the following code:

[print(i.shape, i.dtype) for i in model.inputs]

Similarly, check the output shape and data type of each layer in the model to ensure they align with your expectations:

[print(o.shape, o.dtype) for o in model.outputs]

Debugging Tips

To further debug the issue, try the following:

• Use the function print(l.name, l.input_shape, l.dtype) for l in model.layers to display the name, input shape, and data type of each layer. This can help identify any mismatches in dimensions or data types.
• Expand your input data into the correct shape. In your case, if the original x_train had dimensions (num_samples, timesteps), use x_train = np.expand_dims(x_train, -1) to add a channel dimension. Similarly, check if your target data, y_train, needs to be reshaped.
• Cast your data to a supported data type. Ensure that your data is of type float32 or float64 to be compatible with TensorFlow. Use x = np.asarray(x).astype('float32') for conversion.

By following these steps, you can resolve the error and train your model successfully.