title: UnimplementedError: Fused conv implementation does not support grouped convolutions for now
body: <p>I am trying to build a CNN model to recognise human sketch using the TU-Berlin <a href="http://cybertron.cg.tu-berlin.de/eitz/projects/classifysketch/" rel="noreferrer">dataset</a>. I downloaded the png zip file, imported the data to Google Colab and then split the data into train-test folders. Here is the model:</p>
  
  <pre><code>model = tf.keras.models.Sequential([
      tf.keras.layers.Conv2D(filters = 64, kernel_size = (5,5),padding = 'Same', 
                   activation ='relu', input_shape = target_dims),
      tf.keras.layers.Conv2D(filters = 64, kernel_size = (5,5),padding = 'Same', 
                   activation ='relu'),
      tf.keras.layers.MaxPool2D(pool_size=(2,2)),
      tf.keras.layers.Dropout(0.25),
  
      tf.keras.layers.Conv2D(filters = 128, kernel_size = (3,3),padding = 'Same', 
                   activation ='relu'),
      tf.keras.layers.Conv2D(filters = 128, kernel_size = (3,3),padding = 'Same', 
                   activation ='relu'),
      tf.keras.layers.MaxPool2D(pool_size=(2,2), strides=(2,2)),
      tf.keras.layers.Dropout(0.25),
  
      tf.keras.layers.Conv2D(256, kernel_size=4, strides=1, activation='relu', padding='same'),
      tf.keras.layers.Conv2D(256, kernel_size=4, strides=2, activation='relu', padding='same'),
      tf.keras.layers.Dropout(0.25),
  
      tf.keras.layers.Flatten(),
      tf.keras.layers.Dense(512, activation = "relu"),
      tf.keras.layers.Dropout(0.5),
      tf.keras.layers.Dense(n_classes, activation= "softmax")
  ])
  
  model.compile(optimizer='adam', loss='categorical_crossentropy', metrics=["accuracy"])
  
  model.fit_generator(train_generator, epochs=10, validation_data=val_generator)
  </code></pre>
  
  <p>And I am getting the following error:</p>
  
  <pre><code>UnimplementedError:  Fused conv implementation does not support grouped convolutions for now.
       [[node sequential/conv2d/Relu (defined at &lt;ipython-input-9-36d4624b896d&gt;:1) ]] [Op:__inference_train_function_1358]
  
  Function call stack:
  train_function
  </code></pre>
  
  <p>I would be grateful to any kind of help that will solve this issue. Thank you. </p>
  
  <p>(PS - I am running Tensorflow 2.2.0 and no GPU)</p>