Font size
Worksheetsmi1_05_rnn
Total questions: 11
Worksheet time: 2mins
Did you attempt the last exercise sheet?
Yes
No
I usually have questions (after/during) the lecture/tutorial...
afterwards but don't end up asking
I still need time to go over the material
I can ask them
during but ...
I understand things better when...
I go over the material on my own time
I browse for alternative material
...I've tried everything and I'm still lost
...I'll deal with understanding later. Let's move on.
... we discuss them in lecture and/or tutorial
An RNN can be used to classify an entire time series (T/F)
True
False (we must see the prediction at every time step)
False, RNNs are not classifiers
What's a time series?
The Backpropagation algorithm...
is a learning algorithm
computes the EXACT gradients.
APPROXIMATES the gradients
is a classification model
Backpropagation through time...
is a learning algorithm
computes the exact gradients.
approximates the gradients
is a classification model
Unfolding an RNN in time means
turning the RNN into a feedforward network
recomputing the EXACT same operation at t=1 over and over
Making an RNN go back in time.
Weights in an unfolded RNN...
The weight matrices between sucessive layers are duplicates of W
The W's between time steps are always different.
RNNs are difficult to train because of...
exponential forgetting
unfolding an RNN is very tricky
no one really understands how to implement an RNN
vanishing gradient problem
exponential forgetting (A) vs. (B) vanishing gradients
Both have to do with computational complexity.
(B): applies to feedforward networks only
Both lead to the same problem
(A): activity at t is insensitive to t=0 (B) multiplying small derivatives
Which weights are trained in echo state networks?
W
V
U
x
