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Transformer Architecture and Attention Questions

Comprehensive understanding of Transformer architecture and attention mechanisms including the principles of self attention where queries keys and values are used to compute attention weights with appropriate scaling. Understand scaled dot product attention and multi head attention and why parallel attention heads improve representational capacity. Know positional encoding schemes including absolute positional encodings relative positional encodings rotary position encodings and alternative methods for injecting order information. Be able to explain encoder and decoder components feed forward networks residual connections and layer normalization and their role in training stability and optimization. Discuss attention variants and efficiency improvements such as sparse attention local windowed attention linear attention kernel based approximations and other methods to reduce memory and compute cost along with their trade offs. At senior and staff levels be prepared to reason about scaling Transformers to very large parameter counts including distributed training strategies parameter and data parallelism memory management and attention pattern design for long sequences and efficient inference. Be ready to apply this knowledge to sequence modeling language modeling and sequence transduction tasks and to justify architectural and implementation trade offs.

EasyTechnical
0 practiced
Compute scaled dot-product attention by hand for the following small example: Q = [[1,0],[0,1]], K = [[1,0],[0,1]], V = [[1,2],[3,4]], and d_k = 2. Show intermediate steps (QK^T, scaling, softmax per row) and produce the final attended output and attention weights.
HardTechnical
0 practiced
You must design a summarization API that supports documents up to 10k tokens, handles 5k concurrent requests/day, and meets low-latency goals. Propose an end-to-end design: model choice (encoder-decoder vs long-decoder), chunking/overlap strategy, re-ranking or compression, caching, autoscaling, and cost estimates. Highlight trade-offs and operational risks.
HardSystem Design
0 practiced
Design a distributed training strategy to train a 100-billion parameter Transformer across a multi-node GPU cluster. Address model parallelism choices (tensor vs pipeline vs sequence parallelism), ZeRO optimizer-stage choices, memory balancing, gradient synchronization, checkpointing strategy, and expected communication bottlenecks.
HardSystem Design
0 practiced
Design a verification and CI test-suite to ensure attention implementation correctness across CPU/GPU and mixed-precision (FP16/INT8). Include deterministic numerical tolerance checks, edge-case tests (all padding, single-token sequences), caching and incremental-decoding tests, and performance/regression tests for throughput and memory.
MediumTechnical
0 practiced
Implement T5-style relative position bias (bucketed relative distances) for attention logits. Given relative distances between query and key positions, show pseudocode or code to map distances into buckets and add per-head biases to logits before softmax. Discuss bucketization parameters and sign handling for decoder causality.

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