Estimate Complexity

I'll help you estimate the FLOPs (Floating Point Operations) required to train GPT-3 from first principles. Let's break this down step by step.

1. Model Architecture Parameters

• GPT-3 has 175 billion parameters
• Uses transformer architecture with attention mechanism
• Training involves forward pass, backward pass, and optimizer updates

2. Key Components per Token For each token in the sequence, we need to calculate:

a) Self-Attention

• Query, Key, Value projections: 3 × (n_emb × n_emb)
• Attention scores: n_seq × n_seq × n_emb
• Attention output: n_seq × n_emb × n_emb
• For h=96 attention heads

b) Feed-Forward Network (FFN)

• Two linear transformations
• First projection: n_emb × (4 × n_emb)
• Second projection: (4 × n_emb) × n_emb
• GELU activations

3. Training Details

• Context length: 2048 tokens
• Batch size: ~1.5M tokens per batch (approximate)
• Training tokens: ~300B tokens

4. FLOPs Calculation

Let's calculate for one forward pass through a single token:

a) Self-Attention FLOPs

• QKV projections: 3 × (12288 × 12288) = ~450M FLOPs
• Attention scores: 2048 × 2048 × 12288 = ~50B FLOPs
• Attention output: 2048 × 12288 × 12288 = ~300B FLOPs
• Multiply by 96 heads: ~35T FLOPs

b) FFN FLOPs

• First projection: 12288 × 49152 = ~600M FLOPs
• Second projection: 49152 × 12288 = ~600M FLOPs
• Total FFN: ~1.2B FLOPs

c) Per Token Total

• Forward pass: ~36T FLOPs
• Backward pass (roughly 2x forward): ~72T FLOPs
• Parameter updates (1x forward): ~36T FLOPs
• Total per token: ~144T FLOPs

5. Total Training FLOPs

• Number of tokens: 300B
• FLOPs per token: 144T
• Total FLOPs: 300B × 144T = ~43,200 Zettaflops (4.32 × 10^22 FLOPs)

This is a rough estimate that considers:

• Main computational bottlenecks
• Both forward and backward passes
• Parameter updates
• Major attention and FFN operations

The actual number might be higher due to:

• Additional layer normalizations
• Activation functions
• Memory access operations
• Optimizer-specific computations (Adam)
• Various other overhead operations

This estimate aligns with the general understanding that training large language models requires enormous computational resources, in the order of zettaflops of compute.

Note: This is an approximation based on the model's known architecture and typical training procedures. The actual number could vary based on specific implementation details, optimizations, and hardware-specific considerations.