A Study Guide
Description:
High-quality study guide for CS7643 Quiz 5 Exam (2026), graded A. Covers important deep
learning topics including convolutional neural networks (CNNs), batch normalization, dropout,
optimization methods, and training techniques. Includes concise summaries, equations, and
example problems to make review simple and effective. Perfect for mastering material and
preparing for future quizzes or exams.
Tags: CS7643, Deep Learning, Quiz 5, 2026, Machine Learning, Neural Networks, Study
Guide, GRADED A, Exam Prep, College Notes
CS7643 Quiz 5
Softmax Properties - CORRECT ANSWER ✔✔✔✔✔ - Probabilities
sum to one (gives probability distribution independent of input)
- Performed on sets so invariant to different permutations (permutation
invariant)
- Not linear
- Doubling inputs will put more mass on largest input
- Softmax is differentiable
Softmax Attention vs Final Layer of MLP - CORRECT ANSWER
✔✔✔✔✔ Attention:
- q is an internal hidden state, U is the embeddings of input (previous layer)
- distribution corresponds to a summary of U
MLP:
- q is last hidden state, U is embedding of class labels
- distribution corresponds to labelings (outputs)
, Position Embedding - CORRECT ANSWER ✔✔✔✔✔ - A vector that
depend only on the location in the sequence which is added to an input
placed at that location in the sequence.
- Adds information about the absolute and relative locations of inputs
--> Need this in transformer architectures as they are attention based not
sequentially based
Transformers - CORRECT ANSWER ✔✔✔✔✔ - multi-layer attention
model that is state of the art in most language tasks
- Superior compared to previous attention architectures because:
1. Multi-query hidden-state propagation ("Self-attention") (MOST
IMPORTANT THING)
2. Multi-head attention
3. Residual Connections, LayerNorm
Transformers: Self Attention (Multi-query hidden-state propagation) -
CORRECT ANSWER ✔✔✔✔✔ - improves on softmax attention by
having a controller for every input (size of controller state grows with input
size)
Transformers: Multi-head attention - CORRECT ANSWER ✔✔✔✔✔ -
combines multiple attention 'heads' being trained in the same way on the
same data - but with different weight matrices
- each of the L attention heads yields values for each token; these values
are then multiplied by trained parameters and added
Causal Attention - CORRECT ANSWER ✔✔✔✔✔ - Attention mask
(way of putting a graph structure on transformer)
- Masks out attention weights that don't go from left to right
--> training code outputs a prediction at each token simultaneously (and
takes gradients simultaneously)
--> massively speeds up training (by the size of the context)
--> Not necessary for masked language models like BERT
Attention vs. Seq2Seq Modeling - CORRECT ANSWER ✔✔✔✔✔ -
Seq2Seq passes a single context (the last hidden state) to the decoder,
Attention passes all hidden states to the decoder