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import numpy as np
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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from torch.nn import MultiheadAttention, TransformerEncoder, TransformerEncoderLayer
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from sklearn.metrics import roc_auc_score, average_precision_score
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from utils import torch_corr_x_y, cross_entropy_loss, prototypical_loss
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class AdjacencyMatrixConstructor(nn.Module):
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"""
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Constructs normalized adjacency matrices for graph-based computations.
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These matrices are used for aggregating cell and drug features in the GCN model.
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"""
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def __init__(self, original_adj_mat, device="cpu"):
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super().__init__()
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# Convert numpy array to torch tensor if necessary and move to specified device
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if isinstance(original_adj_mat, np.ndarray):
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original_adj_mat = torch.from_numpy(original_adj_mat).float()
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self.adj = original_adj_mat.to(device)
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self.device = device
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def forward(self):
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"""
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Computes normalized adjacency matrices for cell and drug aggregations.
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Returns four matrices: aggregated cell, aggregated drug, self-cell, and self-drug.
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"""
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with torch.no_grad():
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# Compute degree normalization matrices
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degree_x = torch.pow(torch.sum(self.adj, dim=1) + 1, -0.5)
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degree_y = torch.pow(torch.sum(self.adj, dim=0) + 1, -0.5)
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d_x = torch.diag(degree_x)
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d_y = torch.diag(degree_y)
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# Compute aggregated Laplacian matrices
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agg_cell_lp = torch.mm(torch.mm(d_x, self.adj), d_y) # [num_cells x num_drugs]
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agg_drug_lp = torch.mm(torch.mm(d_y, self.adj.T), d_x) # [num_drugs x num_cells]
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# Compute self-loop Laplacian matrices
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self_cell_lp = torch.diag(torch.add(torch.pow(torch.sum(self.adj, dim=1) + 1, -1), 1))
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self_drug_lp = torch.diag(torch.add(torch.pow(torch.sum(self.adj, dim=0) + 1, -1), 1))
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return (
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agg_cell_lp.to(self.device),
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agg_drug_lp.to(self.device),
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self_cell_lp.to(self.device),
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self_drug_lp.to(self.device)
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)
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class FeatureLoader(nn.Module):
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"""
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Loads and preprocesses cell expression and drug fingerprint features.
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Applies transformations to project features into a common embedding space.
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"""
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def __init__(self, cell_exprs, drug_fingerprints, device="cpu"):
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super().__init__()
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self.device = device
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# Convert input features to torch tensors and move to device
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self.cell_exprs = torch.from_numpy(cell_exprs).float().to(device)
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self.drug_fingerprints = [torch.from_numpy(fp).float().to(device) for fp in drug_fingerprints]
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# Projection layers for drug fingerprints
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self.drug_proj = nn.ModuleList([
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nn.Sequential(
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nn.Linear(fp.shape[1], 512),
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nn.BatchNorm1d(512),
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nn.GELU(),
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nn.Dropout(0.5)
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).to(device) for fp in drug_fingerprints
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])
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# Transformer encoder for drug features
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self.transformer = TransformerEncoder(
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TransformerEncoderLayer(
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d_model=512,
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nhead=8,
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dim_feedforward=2048,
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batch_first=True
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),
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num_layers=1
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).to(device)
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# Normalization layers
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self.cell_norm = nn.LayerNorm(cell_exprs.shape[1]).to(device)
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self.drug_norm = nn.LayerNorm(512).to(device)
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# Encoder for cell features
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self.cell_encoder = nn.Sequential(
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nn.Linear(cell_exprs.shape[1], 1024),
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nn.BatchNorm1d(1024),
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nn.GELU(),
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nn.Dropout(0.5),
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nn.Linear(1024, 512)
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).to(device)
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def forward(self):
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"""
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Processes cell and drug features to produce encoded representations.
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Returns encoded cell and drug features in a common 512-dimensional space.
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"""
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# Normalize and encode cell features
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cell_feat = self.cell_norm(self.cell_exprs) # [num_cells x num_cell_features]
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cell_encoded = self.cell_encoder(cell_feat) # [num_cells x 512]
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# Project and transform drug fingerprints
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projected = [proj(fp) for proj, fp in zip(self.drug_proj, self.drug_fingerprints)] # List of [num_samples x 512]
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stacked = torch.stack(projected, dim=1) # [num_samples x num_drugs x 512]
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drug_feat = self.transformer(stacked) # [num_samples x num_drugs x 512]
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drug_feat = self.drug_norm(drug_feat.mean(dim=1)) # [num_samples x 512]
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return cell_encoded, drug_feat
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class GraphEncoder(nn.Module):
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"""
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Encodes cell and drug features using graph-based aggregation and attention mechanisms.
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Produces final embeddings for cells and drugs.
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"""
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def __init__(self, agg_cell_lp, agg_drug_lp, self_cell_lp, self_drug_lp, device="cpu"):
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super().__init__()
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self.agg_cell_lp = agg_cell_lp
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self.agg_drug_lp = agg_drug_lp
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self.self_cell_lp = self_cell_lp
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self.self_drug_lp = self_drug_lp
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self.device = device
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# Encoder for aggregated cell features
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self.cell_encoder = nn.Sequential(
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nn.Linear(512, 1024),
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nn.BatchNorm1d(1024),
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nn.GELU(),
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nn.Dropout(0.5),
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nn.Linear(1024, 512)
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).to(device)
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# Encoder for aggregated drug features
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self.drug_encoder = nn.Sequential(
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nn.Linear(512, 1024),
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nn.BatchNorm1d(1024),
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nn.GELU(),
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nn.Dropout(0.5),
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nn.Linear(1024, 512)
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).to(device)
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# Attention mechanism for cell-drug interactions
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self.attention = MultiheadAttention(embed_dim=512, num_heads=8, batch_first=True).to(device)
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self.residual = nn.Linear(512, 512).to(device)
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# Final fully connected layer
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self.fc = nn.Sequential(
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nn.Linear(1024, 512),
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nn.BatchNorm1d(512),
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nn.GELU(),
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nn.Dropout(0.5)
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).to(device)
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def forward(self, cell_features, drug_features):
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"""
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Encodes cell and drug features using graph aggregation and attention.
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Returns final cell and drug embeddings.
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"""
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# Aggregate features using Laplacian matrices
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cell_agg = torch.mm(self.agg_cell_lp, drug_features) + torch.mm(self.self_cell_lp, cell_features) # [num_cells x 512]
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drug_agg = torch.mm(self.agg_drug_lp, cell_features) + torch.mm(self.self_drug_lp, drug_features) # [num_drugs x 512]
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# Encode aggregated features
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cell_fc = self.cell_encoder(cell_agg) # [num_cells x 512]
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drug_fc = self.drug_encoder(drug_agg) # [num_drugs x 512]
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# Apply attention mechanism
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attn_output, _ = self.attention(
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query=cell_fc.unsqueeze(0), # [1 x num_cells x 512]
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key=drug_fc.unsqueeze(0), # [1 x num_drugs x 512]
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value=drug_fc.unsqueeze(0) # [1 x num_drugs x 512]
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)
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attn_output = attn_output.squeeze(0) # [num_cells x 512]
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# Combine attention output with residual connection
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cell_emb = cell_fc + self.residual(attn_output) # [num_cells x 512]
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# Apply final activation
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cell_emb = F.gelu(cell_emb) # [num_cells x 512]
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drug_emb = F.gelu(drug_fc) # [num_drugs x 512]
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return cell_emb, drug_emb
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class GraphDecoder(nn.Module):
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"""
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Decodes cell and drug embeddings to predict interaction scores.
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Combines embeddings and applies a correlation-based adjustment.
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"""
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def __init__(self, emb_dim, gamma):
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super().__init__()
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self.gamma = gamma
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# Decoder network for combined embeddings
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self.decoder = nn.Sequential(
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nn.Linear(2 * emb_dim, 1024),
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nn.BatchNorm1d(1024),
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nn.GELU(),
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nn.Dropout(0.2),
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nn.Linear(1024, 1)
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)
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# Learnable weight for balancing scores and correlation
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self.corr_weight = nn.Parameter(torch.tensor(0.5))
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def forward(self, cell_emb, drug_emb):
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"""
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Decodes cell and drug embeddings to produce interaction scores.
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Returns a matrix of interaction probabilities.
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"""
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# Expand embeddings for pairwise combinations
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cell_exp = cell_emb.unsqueeze(1).repeat(1, drug_emb.size(0), 1) # [num_cells x num_drugs x emb_dim]
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drug_exp = drug_emb.unsqueeze(0).repeat(cell_emb.size(0), 1, 1) # [num_cells x num_drugs x emb_dim]
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# Combine cell and drug embeddings
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combined = torch.cat([cell_exp, drug_exp], dim=-1) # [num_cells x num_drugs x 2*emb_dim]
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# Compute interaction scores
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scores = self.decoder(combined.view(-1, 2 * cell_emb.size(1))).view(cell_emb.size(0), drug_emb.size(0)) # [num_cells x num_drugs]
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# Compute correlation between embeddings
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corr = torch_corr_x_y(cell_emb, drug_emb) # [num_cells x num_drugs]
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# Combine scores and correlation with learnable weight
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return torch.sigmoid(self.gamma * (self.corr_weight * scores + (1 - self.corr_weight) * corr))
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class DeepTraCDR(nn.Module):
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"""
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Main Graph Convolutional Network model for predicting cell-drug interactions.
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Combines feature loading, graph encoding, and decoding.
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"""
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def __init__(self, adj_mat, cell_exprs, drug_fingerprints, layer_size, gamma, device="cpu"):
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super().__init__()
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self.device = device
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# Convert adjacency matrix to tensor if necessary
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if isinstance(adj_mat, np.ndarray):
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adj_mat = torch.from_numpy(adj_mat).float()
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self.adj_mat = adj_mat.to(device)
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# Initialize components
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self.construct_adj = AdjacencyMatrixConstructor(self.adj_mat, device=device)
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self.load_feat = FeatureLoader(cell_exprs, drug_fingerprints, device=device)
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# Compute fixed adjacency matrices
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agg_cell, agg_drug, self_cell, self_drug = self.construct_adj()
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# Initialize encoder and decoder
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self.encoder = GraphEncoder(agg_cell, agg_drug, self_cell, self_drug, device=device).to(device)
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self.decoder = GraphDecoder(512, gamma).to(device) # emb_dim fixed to 512
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def forward(self):
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"""
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Performs a full forward pass through the DeepTraCDR model.
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Returns predicted interaction scores and final embeddings.
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"""
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# Load and encode features
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cell_features, drug_features = self.load_feat()
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# Encode features using graph structure
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cell_emb, drug_emb = self.encoder(cell_features, drug_features)
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# Decode to predict interaction scores
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return self.decoder(cell_emb, drug_emb), cell_emb, drug_emb
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class ModelOptimizer:
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"""
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Handles training and evaluation of the DeepTraCDR model.
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Implements early stopping and tracks best performance metrics.
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"""
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def __init__(self, model, train_data, test_data, test_mask, train_mask, adj_matrix, evaluate_fun, lr=0.001, wd=1e-05, epochs=200, test_freq=20, patience=100, device="gpu"):
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self.model = model.to(device)
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self.train_data = train_data.float().to(device)
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self.test_data = test_data.float().to(device)
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self.train_mask = train_mask.to(device)
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self.test_mask_bool = test_mask.to(device).bool()
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self.device = device
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# Convert adjacency matrix to tensor if necessary
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if isinstance(adj_matrix, np.ndarray):
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adj_matrix = torch.from_numpy(adj_matrix).float()
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self.adj_matrix = adj_matrix.to(device)
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self.evaluate_fun = evaluate_fun
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self.optimizer = torch.optim.Adam(self.model.parameters(), lr=lr, weight_decay=wd)
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self.epochs = epochs
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self.test_freq = test_freq
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self.patience = patience
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self.best_auc = 0.0
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self.best_auprc = 0.0
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self.best_weights = None
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self.counter = 0 # Early stopping counter
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self.best_epoch_auc = None
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self.best_epoch_auprc = None
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def train(self):
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"""
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Trains the model with early stopping and evaluates performance.
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Returns the best AUC and AUPRC achieved during training.
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"""
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true_data = torch.masked_select(self.test_data, self.test_mask_bool).cpu().numpy()
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for epoch in range(self.epochs):
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self.model.train()
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# Forward pass and compute loss
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pred_train, cell_emb, drug_emb = self.model()
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ce_loss = cross_entropy_loss(self.train_data, pred_train, self.train_mask)
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proto_loss = prototypical_loss(cell_emb, drug_emb, self.adj_matrix)
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total_loss = 0.7 * ce_loss + 0.3 * proto_loss
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# Backward pass and optimization
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self.optimizer.zero_grad()
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total_loss.backward()
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self.optimizer.step()
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# Evaluate model
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self.model.eval()
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with torch.no_grad():
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# Compute metrics for training data
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train_pred, _, _ = self.model()
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train_pred_masked = torch.masked_select(train_pred, self.train_mask).cpu().numpy()
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train_true_data = torch.masked_select(self.train_data, self.train_mask).cpu().numpy()
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try:
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train_auc = roc_auc_score(train_true_data, train_pred_masked)
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train_auprc = average_precision_score(train_true_data, train_pred_masked)
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except ValueError:
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train_auc, train_auprc = 0.0, 0.0
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# Compute metrics for test data
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pred_eval, _, _ = self.model()
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pred_masked = torch.masked_select(pred_eval, self.test_mask_bool).cpu().numpy()
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try:
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auc = roc_auc_score(true_data, pred_masked)
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auprc = average_precision_score(true_data, pred_masked)
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except ValueError:
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auc, auprc = 0.0, 0.0
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# Update best metrics and weights
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if auc > self.best_auc:
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self.best_auc = auc
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self.best_auprc = auprc
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self.best_weights = self.model.state_dict().copy()
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self.counter = 0
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self.best_epoch_auc = auc
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self.best_epoch_auprc = auprc
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else:
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self.counter += 1
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# Log progress
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if epoch % self.test_freq == 0 or epoch == self.epochs - 1:
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print(f"Epoch {epoch}: Loss={total_loss.item():.4f}, Train AUC={train_auc:.4f}, Train AUPRC={train_auprc:.4f}, Test AUC={auc:.4f}, Test AUPRC={auprc:.4f}")
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# Check early stopping
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|
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if self.counter >= self.patience:
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print(f"\nEarly stopping triggered at epoch {epoch}!")
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print(f"No improvement in AUC for {self.patience} consecutive epochs.")
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break
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# Load best weights
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if self.best_weights is not None:
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self.model.load_state_dict(self.best_weights)
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# Final evaluation
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self.model.eval()
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with torch.no_grad():
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final_pred, _, _ = self.model()
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final_pred_masked = torch.masked_select(final_pred, self.test_mask_bool).cpu().numpy()
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best_auc = roc_auc_score(true_data, final_pred_masked)
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best_auprc = average_precision_score(true_data, final_pred_masked)
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# Print final results
|
|
|
|
print("\nBest Metrics After Training (on Test Data):")
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|
|
|
print(f"AUC: {self.best_auc:.4f}")
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|
|
|
print(f"AUPRC: {self.best_auprc:.4f}")
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return self.best_auc, self.best_auprc |