title: What exactly does tf.keras.layers.Dense do?
body: <h1>My question</h1>
  
  <p>I'm using the Keras to build a convolutional neural network. I ran across the following:</p>
  
  <pre><code>model = tf.keras.Sequential()
  model.add(layers.Dense(10*10*256, use_bias=False, input_shape=(100,)))
  </code></pre>
  
  <p>I'm curious - what exactly mathematically is going on here?</p>
  
  <h1>My best guess</h1>
  
  <p>My guess is that for input of size [100,N], the network will be evaluated N times, once for each training example. The Dense layer created by <code>layers.Dense</code> contains <code>(10*10*256) * (100)</code> parameters that will be updated during backpropagation.</p>