DrugGEN / loss.py
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import torch
def discriminator_loss(generator, discriminator, mol_graph, batch_size, device, grad_pen, lambda_gp, z_edge, z_node):
# Compute loss with real molecules.
logits_real_disc = discriminator(mol_graph)
prediction_real = - torch.mean(logits_real_disc)
# Compute loss with fake molecules.
node, edge, node_sample, edge_sample = generator(z_edge, z_node)
graph = torch.cat((node_sample.view(batch_size, -1), edge_sample.view(batch_size, -1)), dim=-1)
logits_fake_disc = discriminator(graph.detach())
prediction_fake = torch.mean(logits_fake_disc)
# Compute gradient loss.
eps = torch.rand(mol_graph.size(0),1).to(device)
x_int0 = (eps * mol_graph + (1. - eps) * graph).requires_grad_(True)
grad0 = discriminator(x_int0)
d_loss_gp = grad_pen(grad0, x_int0)
# Calculate total loss
d_loss = prediction_fake + prediction_real + d_loss_gp * lambda_gp
return node, edge, d_loss
def generator_loss(generator, discriminator, adj, annot, batch_size):
# Compute loss with fake molecules.
node, edge, node_sample, edge_sample = generator(adj, annot)
graph = torch.cat((node_sample.view(batch_size, -1), edge_sample.view(batch_size, -1)), dim=-1)
logits_fake_disc = discriminator(graph)
prediction_fake = - torch.mean(logits_fake_disc)
g_loss = prediction_fake
return g_loss, node, edge, node_sample, edge_sample