np array shape for conv1d input - numpy

I have a model with conv1d as the first layer.
My data is time series data where each sample consists of 41 time steps where each time step has 4 features.
I have about 1000 samples.
I have specified the input shape of the conve1d layer to be (41,4) as it supposed to be.
However, I keep getting the following error: Input 0 is incompatible with layer conv1d_48: expected ndim=3, found ndim=2.
I suspect that the problem is that the shape of X is (1000,) while the shape of X[0] is (41,4). Has anyone encountered this problem?
Thanks.
l1=Input(shape=(41,4))
x=Conv1D(64,(4))(l1)
x=GlobalMaxPooling1D()(x)
x=Dense(1)(x)
model=Model(l1,x)
model.compile('rmsprop','binary_crossentropy',metrics=['acc'])
model.fit(X,y,32,10)

You defined an expected input on your Conv1D to be be 2D -> (41, 4)
But you give to it an input of shape (41,), be consistant in your definitions !
If you specify the input_shape in your Conv1D layer, you don't need to feed an Input layer to it.
Or you can change the shape of this Input layer to be consistant with this input_shape.

Related

Keras model.fit, dimensions must be equal?

I am a newbie in ML. I have a set of timeseries data with Date and Temp cols., that I want to use for anomaly detection. I used the MinMax scaler on the data and I got an array normal_train_data with shape (200, 0).
Then I used the autoencoder which uses
keras.layers.Dense(128, activation ='sigmoid').
After that, when I call
history = model.fit(normal_train_data, normal_train_data, epochs= 50, batch_size=128, validation_data=(train_data_scaled[:,1:], train_data_scaled[:,1:]) ...)
I get the error:
ValueaError: Dimensions must be equal but are 128 and 0 with input shapes: [?,128], [?,0].
As far as I understand the input has shape (200,0) and the output(1,128).
Can you help me to fix this error please? Thankyou
I tried to use tf.keras.layers.Flatten() in the encoder part. I am not sure if it's ok to use Dense layer or should I choose another.

Tensorflow Keras output layer shape weird error

I am fairly new to TF, Keras and ML in general.
I am trying to implement a very simple MLP with an input shape of (batch_size,3,2) and an output shape of (batch_size,3), that is (if I got it right): for every 3x2 feature, there is a corresponding 3 value array label.
Here is how I create the model:
model = tf.keras.Sequential([
tf.keras.layers.Dense(50,tf.keras.activations.relu,input_shape=((3,2)),
tf.keras.layers.Dense(3)
])
and these are the X and y shapes:
X_train.shape,y_train.shape
TensorShape([64,3,2]),TensorShape([64,3])
On model.fit I am facing a weird error I cannot understand:
ValueError: Dimensions must be equal, but are 3 and 32 for ... with input shapes: [32,3,3] and [32,3]
I have no clue what's going on, I understand the batch size is 32, but where does that [32,3,3] comes from?
Moreover, if from the original 64, I lower the number (shapes) of X_train and y_train, say, to: (19,3,2) and (19,3), I get the following error instead:
InvalidArgumentError: required broadcastable shapes at loc(unknown)
What's even more weird for me is that if I specify a single unit for the output (last) layer, instead of 3 like this:
model = tf.keras.Sequential([
tf.keras.layers.Dense(50,tf.keras.activations.relu,input_shape=((3,2)),
tf.keras.layers.Dense(1)
])
model.fit works, but the predictions have shape (1,3,1) instead of my expected (3,)
I am very confused.
Whenever you have not any idea about the journey of data throughout your model, use model.summary() to see the details and what happens to the shape of data in each layer.
In this case, the input is a 2D array, and the output is a 1D array, and you just used dense layers. Dense layers can not handle 2d features in nature. For example for an image as input, you can not feed it directly to a dense layer. Instead you should use other layers such as Conv2D or Flatten your input (make it 1D) before feeding your data to the dense layer. Otherwise you will get the other dimension in the output.
Inference: If your input dimension and output dimension differs, somewhere in your model, the shape need to be changed. Most common ways to do so, is using a Flatten layer or GlobalAveragePooling and so on.
When you pass an input to a dense layer, the input should be flattened first. There are 2 ways to deal with this:
Way 1: Adding a flatten input as a first layer of your model:
model = Sequential()
model.add(Flatten(input_shape=(3,2)))
model.add(Dense(50, 'relu'))
model.add(Dense(3))
Way 2: Converting the 2D array to 1D before passing the inputs to your model:
X_train = tf.reshape(X_train, shape=([6]))
or
X_train = tf.reshape(X_train, shape=((6,)))
Then change the input shape of the first layer as:
model.add(Dense(50, 'relu', input_shape=(6,))

Keras BatchNormalization layer incompatibility error

I have the following (part of) network architecture:
Obtained by
...
pool = GlobalAvgPool()(gc_2)
predictions = Dense(units=32, activation='relu', use_bias=False)(pool)
predictions = BatchNormalization()(predictions)
...
I am trying to insert a batch normalization layer, but I get the following error:
ValueError: Input 0 of layer batch_normalization_1 is incompatible with the layer: expected ndim=2, found ndim=3. Full shape received: [None, 1, 32]
I am guessing the second dimension is causing this mishap. Is there any way I can get rid of it?
If your model is complied successfully, there is no problem with your model definition.
This is more likely to happen because of the input data shape and dimensions are incompatible with your model's desired input shape.
expected ndim=2, found ndim=3. means that the model requires a 2D tensor with

Input shape for Conv 1D

I am trying to use Conv1D to classify malware based on an 1D array of data.
The shape of the X_train is (7200, 1000).
The shape of the Y_train is (1800, 1000).
The shape of X_test is (7200, 1).
The shape of Y_test(1800, 1).
I have tried doing
model.add(Conv1D(5, 5, input_shape=(X_train[1], 1)))
Does anyone know what input shape I should change it to so it will fit my data?
TensorFlow's Conv1D doesn't have an "input_shape" attribute. Try adding an Input layer before this one. Also, that 1 after the "input_shape" would cause an error. You must mention the parameter name too.

How to correct shape of Keras input into a 3D array

I've a Keras model that when I fit fails with this error
> kerasInput = Input(shape=(None, 47))
> LSTM(..)(kerasInput)
...
> model.fit(realInput, ...)
ValueError: Error when checking input: expected input_1 to have 3 dimensions, but got array with shape (10842, 1)
When looking at my input I found it has a shape of (10842, 1) but for each row it's actually a list of list. I can verify with
> pd.DataFrame(realInput[0]).shape
(260, 47)
How I could correct my input shape?
When trying with keras Reshape layer, the creation of the model fails with:
Model inputs must come from `keras.layers.Input` (thus holding past layer metadata), they cannot be the output of a previous non-Input layer. Here, a tensor specified as input to your model was not an Input tensor, it was generated by layer reshape_8.
Note that input tensors are instantiated via `tensor = keras.layers.Input(shape)`.
The tensor that caused the issue was: reshape_8/Reshape:0
You can use numpy.expand_dims method to convert the shape to 3D.
import numpy as np
np.expand_dims(realInput,axis=0)
Reshape layer keras
https://keras.io/layers/core/#reshape
Use the third parameter as 1
# Something Similar to this
X_train = np.reshape(X_train,(X_train.shape[0],X_train.shape[1],1))
Edit: Added np.reshape method
Refer this repository: https://github.com/NilanshBansal/Stock_Price_Prediction/blob/master/Stock_Price_Prediction_20_days_later_4_LSTM.ipynb
As I said before in the comments. You will need to make sure to reshape your data to match what LSTM expects to receive and also make sure the input_shape is correctly set.
I found this post quite helpful when I struggled with inputting to an LSTM layer. I hope it helps you too : Reshape input for LSTM