GvEM / model.py
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"""
This module provides transformer-based models for processing hierarchical VCF data
"""
import torch
import torch.nn as nn
import torch.nn.functional as F
import math
import logging
from typing import Dict, List, Tuple, Optional, Union, Any
from dataclasses import dataclass
from transformers import PreTrainedModel, PretrainedConfig
from transformers.modeling_outputs import SequenceClassifierOutput
from transformers.utils import ModelOutput
from config import ModelConfig, ConfigManager
from tokenizer import HierarchicalVCFTokenizer
# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
@dataclass
class HierarchicalVCFOutput(ModelOutput):
"""
Args:
loss: Classification loss (if labels provided)
logits: Classification logits
hidden_states: Last hidden states
attentions: Attention weights from all layers
hierarchical_embeddings: Embeddings at each hierarchical level
"""
loss: Optional[torch.FloatTensor] = None
logits: torch.FloatTensor = None
hidden_states: Optional[torch.FloatTensor] = None
attentions: Optional[Tuple[torch.FloatTensor]] = None
hierarchical_embeddings: Optional[Dict[str, torch.FloatTensor]] = None
class HierarchicalVCFConfig(PretrainedConfig):
model_type = "hierarchical-vcf"
def __init__(self,
vocab_sizes: Optional[Dict[str, int]] = None,
embed_dim: int = 64,
transformer_dim: int = 256,
nhead: int = 8,
num_layers: int = 3,
num_classes: int = 2,
hidden_dims: List[int] = None,
dropout: float = 0.1,
activation: str = "gelu",
layer_norm_eps: float = 1e-12,
max_position_embeddings: int = 1024,
use_hierarchical_attention: bool = True,
use_positional_encoding: bool = True,
attention_probs_dropout_prob: float = 0.1,
hidden_dropout_prob: float = 0.1,
classifier_dropout: Optional[float] = None,
**kwargs):
super().__init__(**kwargs)
self.vocab_sizes = vocab_sizes or {
'impact': 10, 'ref': 10, 'alt': 10,
'chromosome': 30, 'pathway': 100, 'gene': 1000
}
self.embed_dim = embed_dim
self.transformer_dim = transformer_dim
self.nhead = nhead
self.num_layers = num_layers
self.num_classes = num_classes
self.hidden_dims = hidden_dims or [512, 256]
self.dropout = dropout
self.activation = activation
self.layer_norm_eps = layer_norm_eps
self.max_position_embeddings = max_position_embeddings
self.use_hierarchical_attention = use_hierarchical_attention
self.use_positional_encoding = use_positional_encoding
self.attention_probs_dropout_prob = attention_probs_dropout_prob
self.hidden_dropout_prob = hidden_dropout_prob
self.classifier_dropout = classifier_dropout
class PositionalEncoding(nn.Module):
def __init__(self, d_model: int, max_len: int = 5000, dropout: float = 0.1):
super().__init__()
self.dropout = nn.Dropout(p=dropout)
pe = torch.zeros(max_len, d_model)
position = torch.arange(0, max_len, dtype=torch.float).unsqueeze(1)
div_term = torch.exp(torch.arange(0, d_model, 2).float() *
(-math.log(10000.0) / d_model))
pe[:, 0::2] = torch.sin(position * div_term)
pe[:, 1::2] = torch.cos(position * div_term)
pe = pe.unsqueeze(0).transpose(0, 1)
self.register_buffer('pe', pe)
def forward(self, x: torch.Tensor) -> torch.Tensor:
"""
Args:
x: Tensor of shape [seq_len, batch_size, d_model]
"""
x = x + self.pe[:x.size(0), :]
return self.dropout(x)
class MutationEmbedder(nn.Module):
def __init__(self, vocab_sizes: Dict[str, int], embed_dim: int = 64, dropout: float = 0.1):
super().__init__()
self.embed_dim = embed_dim
self.mutation_fields = ['impact', 'ref', 'alt']
# Create embedding layers for each field
self.embed_layers = nn.ModuleDict({
field: nn.Embedding(vocab_sizes.get(field, 100), embed_dim, padding_idx=0)
for field in self.mutation_fields
})
# Projection layer to combine embeddings
self.mutation_dim = embed_dim * len(self.mutation_fields)
self.projection = nn.Linear(self.mutation_dim, embed_dim)
self.layer_norm = nn.LayerNorm(embed_dim)
self.dropout = nn.Dropout(dropout)
def forward(self, mutation_batch: Dict[str, torch.Tensor]) -> torch.Tensor:
"""
Args:
mutation_batch: Dict with tensors for each field
Returns:
Embedded mutations tensor [batch_size, seq_len, embed_dim]
"""
embeddings = []
for field in self.mutation_fields:
if field in mutation_batch:
field_emb = self.embed_layers[field](mutation_batch[field])
embeddings.append(field_emb)
if not embeddings:
raise ValueError("No valid mutation fields found in input")
# Concatenate and project
concat_emb = torch.cat(embeddings, dim=-1)
projected_emb = self.projection(concat_emb)
# Apply layer norm and dropout
output = self.layer_norm(projected_emb)
output = self.dropout(output)
return output
class HierarchicalAttention(nn.Module):
def __init__(self, d_model: int, nhead: int = 8, dropout: float = 0.1):
super().__init__()
self.d_model = d_model
self.nhead = nhead
# Multi-head attention
self.multihead_attn = nn.MultiheadAttention(
d_model, nhead, dropout=dropout, batch_first=True
)
# Attention pooling
self.attention_weights = nn.Parameter(torch.randn(d_model))
self.layer_norm = nn.LayerNorm(d_model)
self.dropout = nn.Dropout(dropout)
def forward(self, x: torch.Tensor, mask: Optional[torch.Tensor] = None) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Args:
x: Input tensor [batch_size, seq_len, d_model]
mask: Attention mask [batch_size, seq_len]
Returns:
Tuple of (pooled_output, attention_weights)
"""
# Self-attention
attn_output, attn_weights = self.multihead_attn(x, x, x, key_padding_mask=mask)
attn_output = self.layer_norm(attn_output + x) # Residual connection
# Attention pooling
scores = torch.matmul(attn_output, self.attention_weights) # [batch_size, seq_len]
if mask is not None:
scores = scores.masked_fill(mask, float('-inf'))
attention_probs = F.softmax(scores, dim=-1) # [batch_size, seq_len]
pooled_output = torch.sum(attention_probs.unsqueeze(-1) * attn_output, dim=1) # [batch_size, d_model]
pooled_output = self.dropout(pooled_output)
return pooled_output, attention_probs
class HierarchicalTransformerLayer(nn.Module):
def __init__(self, d_model: int, nhead: int = 8, dim_feedforward: int = 2048,
dropout: float = 0.1, activation: str = "gelu"):
super().__init__()
self.hierarchical_attention = HierarchicalAttention(d_model, nhead, dropout)
# Feed-forward network
self.linear1 = nn.Linear(d_model, dim_feedforward)
self.linear2 = nn.Linear(dim_feedforward, d_model)
self.norm1 = nn.LayerNorm(d_model)
self.norm2 = nn.LayerNorm(d_model)
self.dropout1 = nn.Dropout(dropout)
self.dropout2 = nn.Dropout(dropout)
if activation == "gelu":
self.activation = F.gelu
elif activation == "relu":
self.activation = F.relu
else:
raise ValueError(f"Unsupported activation: {activation}")
def forward(self, x: torch.Tensor, mask: Optional[torch.Tensor] = None) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Args:
x: Input tensor [batch_size, seq_len, d_model]
mask: Attention mask
Returns:
Tuple of (output, attention_weights)
"""
# Hierarchical attention
attn_output, attn_weights = self.hierarchical_attention(x, mask)
x = self.norm1(x.mean(dim=1) + self.dropout1(attn_output)) # Pool input for residual
# Feed-forward
ff_output = self.linear2(self.dropout2(self.activation(self.linear1(x))))
x = self.norm2(x + ff_output)
return x, attn_weights
class HierarchicalVCFModel(PreTrainedModel):
"""
This model processes VCF data in a hierarchical manner:
Mutations -> Genes -> Chromosomes -> Pathways -> Sample
"""
config_class = HierarchicalVCFConfig
def __init__(self, config: HierarchicalVCFConfig):
super().__init__(config)
self.config = config
self.num_classes = config.num_classes
# Embedding layers
self.mutation_embedder = MutationEmbedder(
vocab_sizes=config.vocab_sizes,
embed_dim=config.embed_dim,
dropout=config.hidden_dropout_prob
)
# Positional encoding
if config.use_positional_encoding:
self.pos_encoder = PositionalEncoding(
config.embed_dim,
max_len=config.max_position_embeddings,
dropout=config.hidden_dropout_prob
)
# Hierarchical transformer layers
self.transformer_layers = nn.ModuleList([
HierarchicalTransformerLayer(
d_model=config.embed_dim,
nhead=config.nhead,
dim_feedforward=config.transformer_dim,
dropout=config.attention_probs_dropout_prob,
activation=config.activation
)
for _ in range(config.num_layers)
])
# Hierarchical aggregation layers
self.gene_aggregator = HierarchicalAttention(config.embed_dim, config.nhead)
self.chromosome_aggregator = HierarchicalAttention(config.embed_dim, config.nhead)
self.pathway_aggregator = HierarchicalAttention(config.embed_dim, config.nhead)
# Classification head
classifier_layers = []
input_dim = config.embed_dim
for hidden_dim in config.hidden_dims:
classifier_layers.extend([
nn.Linear(input_dim, hidden_dim),
nn.ReLU(),
nn.Dropout(config.classifier_dropout or config.hidden_dropout_prob)
])
input_dim = hidden_dim
classifier_layers.append(nn.Linear(input_dim, config.num_classes))
self.classifier = nn.Sequential(*classifier_layers)
# Initialize weights
self.apply(self._init_weights)
def _init_weights(self, module):
if isinstance(module, nn.Linear):
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02)
if module.bias is not None:
torch.nn.init.zeros_(module.bias)
elif isinstance(module, nn.Embedding):
torch.nn.init.normal_(module.weight, mean=0.0, std=0.02)
elif isinstance(module, nn.LayerNorm):
torch.nn.init.zeros_(module.bias)
torch.nn.init.ones_(module.weight)
def forward(self,
input_data: Dict[str, Any],
labels: Optional[torch.Tensor] = None,
output_attentions: bool = False,
output_hidden_states: bool = False,
return_dict: bool = True) -> Union[Tuple, HierarchicalVCFOutput]:
"""
Args:
input_data: Hierarchical input data from data collator
labels: Labels for supervised learning
output_attentions: Whether to output attention weights
output_hidden_states: Whether to output hidden states
return_dict: Whether to return ModelOutput object
Returns:
HierarchicalVCFOutput or tuple of outputs
"""
batch_samples = input_data['samples']
batch_size = len(batch_samples)
sample_embeddings = []
all_attentions = [] if output_attentions else None
hierarchical_embeddings = {} if output_hidden_states else None
for sample_idx, sample in enumerate(batch_samples):
sample_embedding = self._process_sample(
sample,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states
)
if output_attentions:
sample_embedding, sample_attentions = sample_embedding
all_attentions.append(sample_attentions)
if output_hidden_states:
sample_embedding, sample_hierarchical = sample_embedding
for level, emb in sample_hierarchical.items():
if level not in hierarchical_embeddings:
hierarchical_embeddings[level] = []
hierarchical_embeddings[level].append(emb)
sample_embeddings.append(sample_embedding)
# Stack sample embeddings
if sample_embeddings:
hidden_states = torch.stack(sample_embeddings) # [batch_size, embed_dim]
else:
hidden_states = torch.zeros(batch_size, self.config.embed_dim, device=self.device)
# Classification
logits = self.classifier(hidden_states)
# Compute loss if labels provided
loss = None
if labels is not None:
if self.config.num_classes == 1:
# Regression
loss_fct = nn.MSELoss()
loss = loss_fct(logits.squeeze(), labels.squeeze())
else:
# Classification
loss_fct = nn.CrossEntropyLoss()
loss = loss_fct(logits.view(-1, self.config.num_classes), labels.view(-1))
if not return_dict:
output = (logits,)
if output_hidden_states:
output = output + (hidden_states,)
if output_attentions:
output = output + (all_attentions,)
if loss is not None:
output = (loss,) + output
return output
return HierarchicalVCFOutput(
loss=loss,
logits=logits,
hidden_states=hidden_states,
attentions=all_attentions,
hierarchical_embeddings=hierarchical_embeddings
)
def _process_sample(self,
sample: Dict[str, Any],
output_attentions: bool = False,
output_hidden_states: bool = False) -> torch.Tensor:
"""
Process a single hierarchical sample.
Args:
sample: Single sample from batch
output_attentions: Whether to return attention weights
output_hidden_states: Whether to return hierarchical embeddings
Returns:
Sample embedding tensor or tuple with additional outputs
"""
pathway_embeddings = []
sample_attentions = {} if output_attentions else None
sample_hierarchical = {} if output_hidden_states else None
for pathway_token, chromosomes in sample.items():
chromosome_embeddings = []
for chrom_token, genes in chromosomes.items():
gene_embeddings = []
for gene_token, mutations in genes.items():
# Process mutations for this gene
gene_embedding = self._process_gene_mutations(
mutations,
output_attentions=output_attentions
)
if output_attentions:
gene_embedding, gene_attentions = gene_embedding
if 'gene_level' not in sample_attentions:
sample_attentions['gene_level'] = []
sample_attentions['gene_level'].append(gene_attentions)
gene_embeddings.append(gene_embedding)
if gene_embeddings:
# Aggregate genes to chromosome level
gene_tensor = torch.stack(gene_embeddings).unsqueeze(0) # [1, num_genes, embed_dim]
chrom_embedding, chrom_attention = self.chromosome_aggregator(gene_tensor)
chrom_embedding = chrom_embedding.squeeze(0) # [embed_dim]
chromosome_embeddings.append(chrom_embedding)
if output_attentions:
if 'chromosome_level' not in sample_attentions:
sample_attentions['chromosome_level'] = []
sample_attentions['chromosome_level'].append(chrom_attention)
if chromosome_embeddings:
# Aggregate chromosomes to pathway level
chrom_tensor = torch.stack(chromosome_embeddings).unsqueeze(0) # [1, num_chroms, embed_dim]
pathway_embedding, pathway_attention = self.pathway_aggregator(chrom_tensor)
pathway_embedding = pathway_embedding.squeeze(0) # [embed_dim]
pathway_embeddings.append(pathway_embedding)
if output_attentions:
if 'pathway_level' not in sample_attentions:
sample_attentions['pathway_level'] = []
sample_attentions['pathway_level'].append(pathway_attention)
if output_hidden_states:
sample_hierarchical['pathway_embeddings'] = pathway_embeddings
if pathway_embeddings:
# Aggregate pathways to sample level
pathway_tensor = torch.stack(pathway_embeddings).unsqueeze(0) # [1, num_pathways, embed_dim]
sample_embedding, sample_attention = self.gene_aggregator(pathway_tensor) # Reuse gene aggregator
sample_embedding = sample_embedding.squeeze(0) # [embed_dim]
if output_attentions:
sample_attentions['sample_level'] = sample_attention
else:
# Handle empty sample
sample_embedding = torch.zeros(self.config.embed_dim, device=self.device)
# Prepare return value
result = sample_embedding
if output_attentions and output_hidden_states:
result = (result, sample_attentions, sample_hierarchical)
elif output_attentions:
result = (result, sample_attentions)
elif output_hidden_states:
result = (result, sample_hierarchical)
return result
def _process_gene_mutations(self,
mutations: Dict[str, Any],
output_attentions: bool = False) -> torch.Tensor:
"""
Process mutations for a single gene.
Args:
mutations: Mutation data for gene
output_attentions: Whether to return attention weights
Returns:
Gene embedding tensor
"""
# Handle masked format from data collator
mutation_tensors = {}
attention_mask = None
for field in ['impact', 'ref', 'alt']:
if field in mutations:
if isinstance(mutations[field], dict) and 'tokens' in mutations[field]:
# Masked format
mutation_tensors[field] = torch.tensor(mutations[field]['tokens'], device=self.device)
if attention_mask is None:
attention_mask = torch.tensor(mutations[field]['mask'], device=self.device).bool()
else:
# Direct format
mutation_tensors[field] = torch.tensor(mutations[field], device=self.device)
if not mutation_tensors:
return torch.zeros(self.config.embed_dim, device=self.device)
# Embed mutations
mutation_embeddings = self.mutation_embedder(mutation_tensors) # [seq_len, embed_dim]
# Add positional encoding if enabled
if self.config.use_positional_encoding:
mutation_embeddings = mutation_embeddings.unsqueeze(1) # [seq_len, 1, embed_dim]
mutation_embeddings = self.pos_encoder(mutation_embeddings)
mutation_embeddings = mutation_embeddings.squeeze(1) # [seq_len, embed_dim]
# Apply transformer layers
mutation_embeddings = mutation_embeddings.unsqueeze(0) # [1, seq_len, embed_dim]
layer_attentions = [] if output_attentions else None
for layer in self.transformer_layers:
mutation_embeddings, layer_attention = layer(mutation_embeddings, attention_mask)
mutation_embeddings = mutation_embeddings.unsqueeze(1) # Add seq dim back
if output_attentions:
layer_attentions.append(layer_attention)
# Pool to get gene representation
if attention_mask is not None:
# Masked pooling
mask_expanded = attention_mask.unsqueeze(-1).expand_as(mutation_embeddings.squeeze(0))
masked_embeddings = mutation_embeddings.squeeze(0) * mask_expanded.float()
gene_embedding = masked_embeddings.sum(dim=0) / mask_expanded.sum(dim=0).clamp(min=1)
else:
# Simple mean pooling
gene_embedding = mutation_embeddings.mean(dim=1).squeeze(0)
if output_attentions:
return gene_embedding, layer_attentions
return gene_embedding
@property
def device(self) -> torch.device:
"""Get model device."""
return next(self.parameters()).device
def create_model_from_config(config_manager: ConfigManager,
tokenizer: HierarchicalVCFTokenizer) -> HierarchicalVCFModel:
"""
Args:
config_manager: Configuration manager
tokenizer: Tokenizer instance
task_type: Type of task ('classification', 'regression')
Returns:
Configured model
"""
model_config = config_manager.model_config
# Create Hugging Face config
hf_config = HierarchicalVCFConfig(
vocab_sizes=tokenizer.get_all_vocab_sizes(),
embed_dim=model_config.embed_dim,
transformer_dim=model_config.transformer_dim,
nhead=model_config.nhead,
num_layers=model_config.num_layers,
num_classes=model_config.num_classes,
hidden_dims=model_config.hidden_dims,
dropout=model_config.dropout
)
# Create model based on task type
model = HierarchicalVCFModel(hf_config)
return model
# Model utilities
class ModelTrainer:
"""
Training utilities for Hierarchical VCF Model.
"""
def __init__(self,
model: HierarchicalVCFModel,
train_dataloader,
val_dataloader,
optimizer: Optional[torch.optim.Optimizer] = None,
scheduler: Optional[torch.optim.lr_scheduler._LRScheduler] = None,
device: Optional[torch.device] = None):
self.model = model
self.train_dataloader = train_dataloader
self.val_dataloader = val_dataloader
self.device = device or torch.device('cuda' if torch.cuda.is_available() else 'cpu')
# Move model to device
self.model.to(self.device)
# Default optimizer
if optimizer is None:
self.optimizer = torch.optim.AdamW(
model.parameters(),
lr=1e-4,
weight_decay=0.01
)
else:
self.optimizer = optimizer
self.scheduler = scheduler
# Training metrics
self.train_losses = []
self.val_losses = []
self.val_accuracies = []
def train_epoch(self) -> float:
"""Train for one epoch."""
self.model.train()
total_loss = 0.0
num_batches = 0
for batch in self.train_dataloader:
self.optimizer.zero_grad()
# Move data to device
if 'labels' in batch:
labels = batch['labels'].to(self.device)
else:
labels = None
# Forward pass
outputs = self.model(batch, labels=labels)
loss = outputs.loss if hasattr(outputs, 'loss') else outputs[0]
# Backward pass
loss.backward()
self.optimizer.step()
total_loss += loss.item()
num_batches += 1
if self.scheduler:
self.scheduler.step()
avg_loss = total_loss / max(num_batches, 1)
self.train_losses.append(avg_loss)
return avg_loss
def validate(self) -> Tuple[float, float]:
"""Validate model."""
self.model.eval()
total_loss = 0.0
correct_predictions = 0
total_predictions = 0
num_batches = 0
with torch.no_grad():
for batch in self.val_dataloader:
# Move data to device
if 'labels' in batch:
labels = batch['labels'].to(self.device)
else:
continue # Skip if no labels
# Forward pass
outputs = self.model(batch, labels=labels)
loss = outputs.loss if hasattr(outputs, 'loss') else outputs[0]
logits = outputs.logits if hasattr(outputs, 'logits') else outputs[1]
total_loss += loss.item()
# Calculate accuracy
predictions = torch.argmax(logits, dim=-1)
correct_predictions += (predictions == labels).sum().item()
total_predictions += labels.size(0)
num_batches += 1
avg_loss = total_loss / max(num_batches, 1)
accuracy = correct_predictions / max(total_predictions, 1)
self.val_losses.append(avg_loss)
self.val_accuracies.append(accuracy)
return avg_loss, accuracy
def train(self, num_epochs: int, save_path: Optional[str] = None) -> Dict[str, List[float]]:
"""
Train model for specified number of epochs.
Args:
num_epochs: Number of training epochs
save_path: Path to save best model
Returns:
Training history
"""
best_val_loss = float('inf')
logger.info(f"Starting training for {num_epochs} epochs...")
for epoch in range(num_epochs):
# Train
train_loss = self.train_epoch()
# Validate
val_loss, val_accuracy = self.validate()
logger.info(
f"Epoch {epoch+1}/{num_epochs}: "
f"Train Loss: {train_loss:.4f}, "
f"Val Loss: {val_loss:.4f}, "
f"Val Accuracy: {val_accuracy:.4f}"
)
# Save best model
if save_path and val_loss < best_val_loss:
best_val_loss = val_loss
self.model.save_pretrained(save_path)
logger.info(f"Saved best model to {save_path}")
return {
'train_losses': self.train_losses,
'val_losses': self.val_losses,
'val_accuracies': self.val_accuracies
}
# Example usage and testing
if __name__ == "__main__":
from tokenizer import create_tokenizer_from_config
from dataset import create_data_module_from_config
# Create configuration
config_manager = ConfigManager()
config_manager.model_config.embed_dim = 32
config_manager.model_config.num_classes = 2
# Create tokenizer and model
tokenizer = create_tokenizer_from_config(config_manager)
# Build vocabulary with example data
example_data = {
'sample1': {
'pathway1': {
'chr1': {
'gene1': [
{'impact': 'HIGH', 'reference': 'A', 'alternate': 'T'}
]
}
}
}
}
tokenizer.build_vocabulary(example_data)
# Create model
model = create_model_from_config(config_manager, tokenizer)
print(f"Model created with {sum(p.numel() for p in model.parameters())} parameters")
print(f"Model config: {model.config}")
# Test forward pass with dummy data
dummy_batch = {
'samples': [example_data['sample1']],
'batch_size': 1
}
with torch.no_grad():
outputs = model(dummy_batch)
print(f"Output logits shape: {outputs.logits.shape}")
print(f"Output logits: {outputs.logits}")