FastChemTokenizer / benchmark /latent_visualization_legacy.py
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#!/usr/bin/env python3
"""
Latent Space Visualization for Molecule VAE Models
Integrated with existing benchmark pipeline structure
"""
import os
import time
import random
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
from matplotlib.colors import ListedColormap
from pathlib import Path
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.utils.data import DataLoader, Dataset
from sklearn.manifold import TSNE
from sklearn.decomposition import PCA
from tqdm import tqdm
from rdkit import Chem
from rdkit import RDLogger
RDLogger.DisableLog('rdApp.*')
os.environ["KMP_DUPLICATE_LIB_OK"] = "TRUE"
# Import from existing benchmark code
from transformers import AutoTokenizer
try:
from FastChemTokenizer import FastChemTokenizer
except ImportError:
print("FastChemTokenizer not found. Please ensure it's in your PYTHONPATH.")
FastChemTokenizer = None
# Set seeds for reproducibility
def set_seed(seed=42):
torch.manual_seed(seed)
torch.cuda.manual_seed_all(seed)
np.random.seed(seed)
random.seed(seed)
os.environ['PYTHONHASHSEED'] = str(seed)
torch.backends.cudnn.deterministic = True
torch.backends.cudnn.benchmark = False
set_seed(42)
# Device setup
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
class TokenizerWrapper:
def __init__(self, tokenizer, name, bos_token="<s>", eos_token="</s>", pad_token="<pad>", unk_token="<unk>"):
self.tokenizer = tokenizer
self.name = name
self.bos_token = bos_token
self.eos_token = eos_token
self.pad_token = pad_token
self.unk_token = unk_token
if hasattr(tokenizer, 'add_special_tokens'):
tokenizer.add_special_tokens({
'bos_token': bos_token,
'eos_token': eos_token,
'pad_token': pad_token,
'unk_token': unk_token
})
def encode(self, smiles: str, add_special_tokens: bool = True):
if isinstance(self.tokenizer, FastChemTokenizer):
# 1. get ids directly
ids = self.tokenizer.encode(smiles) # ← no .tokenize() here
# 2. add specials ourselves
if add_special_tokens:
ids = [self.tokenizer.bos_token_id] + ids + [self.tokenizer.eos_token_id]
return {'input_ids': ids}
else:
# Hugging-Face style tokenizer
return self.tokenizer(
smiles,
add_special_tokens=add_special_tokens,
return_attention_mask=False,
return_tensors=None
)
def decode(self, token_ids, skip_special_tokens=True):
if isinstance(self.tokenizer, FastChemTokenizer):
# 1. map single ids → tokens
tokens = [self.tokenizer.id_to_token.get(tid, self.tokenizer.unk_token)
for tid in token_ids]
# 2. drop specials if requested
if skip_special_tokens:
specials = {self.tokenizer.bos_token,
self.tokenizer.eos_token,
self.tokenizer.pad_token,
self.tokenizer.unk_token} # add any others you use
tokens = [t for t in tokens if t not in specials]
# 3. detokenise
if hasattr(self.tokenizer, 'detokenize'):
return self.tokenizer.detokenize(tokens)
else:
return "".join(tokens) # chemistry tokens are atomic
else:
return self.tokenizer.decode(token_ids, skip_special_tokens=skip_special_tokens)
def __len__(self):
if isinstance(self.tokenizer, FastChemTokenizer):
# FastChemTokenizer uses ._vocab or .vocab depending on version
return len(getattr(self.tokenizer, 'vocab',
getattr(self.tokenizer, '_vocab', self.tokenizer)))
else:
return len(self.tokenizer)
def get_vocab(self):
if isinstance(self.tokenizer, FastChemTokenizer):
return self.tokenizer.vocab
else:
return self.tokenizer.get_vocab()
@property
def bos_token_id(self):
return self.tokenizer.bos_token_id
@property
def eos_token_id(self):
return self.tokenizer.eos_token_id
@property
def pad_token_id(self):
return self.tokenizer.pad_token_id
@property
def unk_token_id(self):
return self.tokenizer.unk_token_id
def collate_fn(batch, tokenizer, max_length=128):
encodings = [tokenizer.encode(s, add_special_tokens=True) for s in batch]
input_ids = [e['input_ids'] for e in encodings]
max_len = min(max(len(ids) for ids in input_ids), max_length)
padded = []
lengths = []
pad_token_id = tokenizer.tokenizer.pad_token_id # FIXED: dynamic
for ids in input_ids:
if len(ids) > max_length:
ids = ids[:max_length]
else:
ids = ids + [pad_token_id] * (max_len - len(ids))
padded.append(ids)
lengths.append(min(len(ids), max_length))
return torch.tensor(padded, dtype=torch.long), torch.tensor(lengths, dtype=torch.long)
class SmilesDataset(Dataset):
def __init__(self, smiles_list):
self.smiles_list = smiles_list
def __len__(self):
return len(self.smiles_list)
def __getitem__(self, idx):
return self.smiles_list[idx]
class MoleculeVAE(nn.Module):
def __init__(self, vocab_size, embed_dim=256, hidden_dim=512, latent_dim=128, num_layers=2,
pad_token_id=0, bos_token_id=1, eos_token_id=2):
super().__init__()
self.vocab_size = vocab_size
self.embed_dim = embed_dim
self.hidden_dim = hidden_dim
self.latent_dim = latent_dim
self.num_layers = num_layers
self.pad_token_id = pad_token_id
self.bos_token_id = bos_token_id
self.eos_token_id = eos_token_id
self.embedding = nn.Embedding(vocab_size, embed_dim, padding_idx=pad_token_id)
self.encoder_lstm = nn.LSTM(embed_dim, hidden_dim, num_layers, batch_first=True, bidirectional=True)
self.fc_mu = nn.Linear(hidden_dim * 2, latent_dim)
self.fc_logvar = nn.Linear(hidden_dim * 2, latent_dim)
self.decoder_lstm = nn.LSTM(embed_dim, hidden_dim, num_layers, batch_first=True)
self.fc_out = nn.Linear(hidden_dim, vocab_size)
self.latent2hidden = nn.Linear(latent_dim, num_layers * hidden_dim)
self.latent2cell = nn.Linear(latent_dim, num_layers * hidden_dim)
self._init_weights()
def _init_weights(self):
for m in self.modules():
if isinstance(m, nn.Linear):
nn.init.xavier_uniform_(m.weight)
if m.bias is not None:
nn.init.zeros_(m.bias)
elif isinstance(m, nn.LSTM):
for name, param in m.named_parameters():
if 'weight' in name:
nn.init.orthogonal_(param)
elif 'bias' in name:
nn.init.zeros_(param)
def encode(self, x, lengths):
embedded = self.embedding(x)
packed = nn.utils.rnn.pack_padded_sequence(embedded, lengths.cpu(), batch_first=True, enforce_sorted=False)
packed_out, (hidden, _) = self.encoder_lstm(packed)
h_forward = hidden[-2]
h_backward = hidden[-1]
h = torch.cat([h_forward, h_backward], dim=1)
mu = self.fc_mu(h)
logvar = self.fc_logvar(h)
return mu, logvar
def reparameterize(self, mu, logvar):
if self.training:
std = torch.exp(0.5 * logvar)
eps = torch.randn_like(std)
return mu + eps * std
else:
return mu
def decode(self, z, max_length=128, mode="greedy", temperature=1.0):
"""
Decode latent vector z into a sequence.
Returns full logits at each step.
PATCHED: stops generation when EOS is predicted.
"""
batch_size = z.size(0)
device = z.device
# Initialize hidden states from latent
h0 = self.latent2hidden(z).view(self.num_layers, batch_size, self.hidden_dim)
c0 = self.latent2cell(z).view(self.num_layers, batch_size, self.hidden_dim)
hidden = (h0, c0)
# Start with BOS token — shape: (batch_size, 1)
input_token = torch.full((batch_size, 1), self.bos_token_id, dtype=torch.long, device=device)
logits = []
finished = torch.zeros(batch_size, dtype=torch.bool, device=device) # ← TRACK FINISHED SEQS
for _ in range(max_length):
embedded = self.embedding(input_token) # (batch, 1, embed_dim)
output, hidden = self.decoder_lstm(embedded, hidden)
logit = self.fc_out(output) # (batch, 1, vocab)
logits.append(logit)
if mode == "greedy":
input_token = logit.argmax(dim=-1) # (batch, 1)
elif mode == "sample":
probs = torch.softmax(logit.squeeze(1) / temperature, dim=-1) # (batch, vocab)
input_token = torch.multinomial(probs, 1) # (batch, 1)
else:
raise ValueError(f"Unknown decode mode: {mode}")
# ← EARLY STOPPING AT EOS
just_finished = (input_token.squeeze(1) == self.eos_token_id)
finished |= just_finished
input_token[finished] = self.pad_token_id # pad finished sequences
if finished.all():
break
return torch.cat(logits, dim=1) # (batch, seq_len, vocab)
def forward(self, input_ids, lengths, target_seq=None, teacher_forcing_ratio=0.0, temperature=1.0):
mu, logvar = self.encode(input_ids, lengths)
z = self.reparameterize(mu, logvar)
if self.training and target_seq is not None and teacher_forcing_ratio > 0:
# Training with teacher forcing
batch_size, seq_len = target_seq.size()
device = target_seq.device
# Initialize hidden states
h0 = self.latent2hidden(z).view(self.num_layers, batch_size, self.hidden_dim)
c0 = self.latent2cell(z).view(self.num_layers, batch_size, self.hidden_dim)
hidden = (h0, c0)
logits = []
input_token = target_seq[:, 0].unsqueeze(1) # BOS
for t in range(1, seq_len):
embedded = self.embedding(input_token)
output, hidden = self.decoder_lstm(embedded, hidden)
logit = self.fc_out(output)
logits.append(logit)
use_teacher = torch.rand(1).item() < teacher_forcing_ratio
if use_teacher:
input_token = target_seq[:, t].unsqueeze(1)
else:
input_token = logit.argmax(dim=-1)
logits = torch.cat(logits, dim=1)
else:
# Inference mode
max_len = target_seq.size(1) if target_seq is not None else 128
logits = self.decode(z, max_length=max_len, mode="greedy", temperature=temperature)
return logits, mu, logvar
class LatentSpaceVisualizer:
def __init__(self, model_path, tokenizer, device='cuda' if torch.cuda.is_available() else 'cpu'):
self.device = device
self.tokenizer = tokenizer
self.model = self.load_model(model_path)
def load_model(self, model_path):
"""Load the trained VAE model"""
checkpoint = torch.load(model_path, map_location=self.device)
# Extract model parameters from checkpoint
if 'model_state_dict' in checkpoint:
state_dict = checkpoint['model_state_dict']
else:
state_dict = checkpoint
# Get vocab size from tokenizer
vocab_size = len(self.tokenizer)
pad_token_id = self.tokenizer.tokenizer.pad_token_id
# Initialize model with correct parameters
model = MoleculeVAE(vocab_size=vocab_size, pad_token_id=pad_token_id)
model.load_state_dict(state_dict)
model.to(self.device)
model.eval()
return model
def encode_molecules(self, smiles_list, batch_size=32):
"""Encode molecules to latent space"""
dataset = SmilesDataset(smiles_list)
dataloader = DataLoader(
dataset,
batch_size=batch_size,
shuffle=False,
collate_fn=lambda batch: collate_fn(batch, self.tokenizer, max_length=128)
)
all_mus = []
with torch.no_grad():
for input_ids, lengths in tqdm(dataloader, desc="Encoding molecules"):
input_ids = input_ids.to(self.device)
lengths = lengths.to(self.device)
mu, logvar = self.model.encode(input_ids, lengths)
all_mus.append(mu.cpu().numpy())
return np.concatenate(all_mus, axis=0)
def create_grid_latent_points(self, grid_size=100, z_range=4):
"""Create a grid of points in 2D latent space"""
x = np.linspace(-z_range, z_range, grid_size)
y = np.linspace(-z_range, z_range, grid_size)
xx, yy = np.meshgrid(x, y)
# Create circular mask
center = grid_size // 2
radius = grid_size // 2
y_coords, x_coords = np.ogrid[:grid_size, :grid_size]
mask = (x_coords - center) ** 2 + (y_coords - center) ** 2 <= radius ** 2
return xx, yy, mask
def classify_latent_points(self, latent_points, dim1=0, dim2=1, additional_dim=None):
"""
Classify latent points by chemical validity (RDKit parseable)
Returns: 0 for invalid/unparseable molecules, 1 for valid molecules
"""
classifications = []
with torch.no_grad():
# Process in batches to avoid memory issues
batch_size = 32
for i in range(0, len(latent_points), batch_size):
batch_points = latent_points[i:i+batch_size]
# Create full latent vectors (sample from normal for other dimensions)
full_z = torch.randn(len(batch_points), self.model.latent_dim, device=self.device) * 0.1
full_z[:, dim1] = torch.FloatTensor(batch_points[:, 0]).to(self.device)
full_z[:, dim2] = torch.FloatTensor(batch_points[:, 1]).to(self.device)
# If additional dimension specified (for z2 plots)
if additional_dim is not None:
if isinstance(additional_dim, dict):
for dim_idx, dim_val in additional_dim.items():
full_z[:, dim_idx] = dim_val
try:
# Decode to SMILES
logits = self.model.decode(full_z, max_length=64, temperature=0.8)
predictions = torch.argmax(logits, dim=-1)
# Check chemical validity for each decoded molecule
batch_classes = []
for pred in predictions:
pred_ids = pred.cpu().tolist()
# Remove padding and special tokens
pad_id = self.tokenizer.tokenizer.pad_token_id
eos_id = self.tokenizer.tokenizer.eos_token_id
# Trim at EOS or pad
for j, token_id in enumerate(pred_ids):
if token_id in [pad_id, eos_id]:
pred_ids = pred_ids[:j]
break
try:
decoded_smiles = self.tokenizer.decode(pred_ids, skip_special_tokens=True)
# Test chemical validity with RDKit
mol = Chem.MolFromSmiles(decoded_smiles)
if mol is None:
# Invalid/unparseable molecule
batch_classes.append(0)
else:
# Valid, RDKit-parseable molecule
batch_classes.append(1)
except Exception:
# Decoding or parsing failed - invalid
batch_classes.append(0)
classifications.extend(batch_classes)
except Exception as e:
# If decoding fails, all points in batch are invalid
classifications.extend([0] * len(batch_points))
return np.array(classifications)
def plot_latent_space_interpolation(self, grid_size=100, z_range=4, save_path=None):
"""
Create latent space interpolation plots similar to the reference images
"""
fig, axes = plt.subplots(2, 4, figsize=(20, 10))
axes = axes.flatten()
# Create color map (RED for invalid molecules, GREEN for valid molecules)
colors = ['#FF4444', '#44AA44'] # Red (invalid) and Green (valid)
cmap = ListedColormap(colors)
plot_idx = 0
# First row: different dimension pairs
dimension_pairs = [(0, 1), (2, 3), (4, 5), (6, 7)]
for dim_pair in dimension_pairs:
dim1, dim2 = dim_pair
# Create grid
xx, yy, mask = self.create_grid_latent_points(grid_size, z_range)
# Get points within circular boundary
valid_points = []
valid_coords = []
for i in range(grid_size):
for j in range(grid_size):
if mask[i, j]:
valid_points.append([xx[i, j], yy[i, j]])
valid_coords.append([i, j])
valid_points = np.array(valid_points)
# Classify points based on chemical validity
print(f"Classifying latent space chemical validity for dimensions {dim1}, {dim2}...")
classifications = self.classify_latent_points(valid_points, dim1, dim2)
# Create classification grid
class_grid = np.zeros((grid_size, grid_size))
class_grid.fill(np.nan) # Fill with NaN for areas outside circle
for point_idx, (i, j) in enumerate(valid_coords):
class_grid[i, j] = classifications[point_idx]
# Plot
ax = axes[plot_idx]
im = ax.imshow(class_grid, extent=[-z_range, z_range, -z_range, z_range],
origin='lower', cmap=cmap, alpha=0.8, vmin=0, vmax=1)
# Add concentric circles
circles = [1, 2, 3, 4]
for radius in circles:
if radius <= z_range:
circle = plt.Circle((0, 0), radius, fill=False, color='black',
alpha=0.3, linewidth=0.5)
ax.add_patch(circle)
# Set labels and title
ax.set_xlabel(f'Latent dimension z{dim1}')
ax.set_ylabel(f'Latent dimension z{dim2}')
ax.set_title('SMILES')
ax.set_xlim(-z_range, z_range)
ax.set_ylim(-z_range, z_range)
ax.set_aspect('equal')
plot_idx += 1
# Second row: fix z0, z1 and vary z2
for z2_val in [-2, -1, 1, 2]:
dim1, dim2 = 0, 1 # Use z0 and z1 for x,y
# Create grid
xx, yy, mask = self.create_grid_latent_points(grid_size, z_range)
# Get points within circular boundary
valid_points = []
valid_coords = []
for i in range(grid_size):
for j in range(grid_size):
if mask[i, j]:
valid_points.append([xx[i, j], yy[i, j]])
valid_coords.append([i, j])
valid_points = np.array(valid_points)
# Classify points with z2 fixed - check chemical validity
print(f"Classifying latent space chemical validity for z0, z1 with z2 = {z2_val}...")
classifications = self.classify_latent_points(
valid_points, dim1, dim2,
additional_dim={2: z2_val}
)
# Create classification grid
class_grid = np.zeros((grid_size, grid_size))
class_grid.fill(np.nan)
for point_idx, (i, j) in enumerate(valid_coords):
class_grid[i, j] = classifications[point_idx]
# Plot
ax = axes[plot_idx]
im = ax.imshow(class_grid, extent=[-z_range, z_range, -z_range, z_range],
origin='lower', cmap=cmap, alpha=0.8, vmin=0, vmax=1)
# Add concentric circles
for radius in circles:
if radius <= z_range:
circle = plt.Circle((0, 0), radius, fill=False, color='black',
alpha=0.3, linewidth=0.5)
ax.add_patch(circle)
ax.set_xlabel('Latent dimension z0')
ax.set_ylabel('Latent dimension z1')
ax.set_title(f'SMILES; z2 = {z2_val}')
ax.set_xlim(-z_range, z_range)
ax.set_ylim(-z_range, z_range)
ax.set_aspect('equal')
plot_idx += 1
plt.suptitle(f'Latent Space Chemical Validity - {self.tokenizer.name}\n(Red: Invalid molecules, Green: Valid molecules)', fontsize=16)
plt.tight_layout()
if save_path:
plt.savefig(save_path, dpi=300, bbox_inches='tight')
plt.show()
def plot_molecule_embeddings(self, smiles_list, method='tsne', save_path=None):
"""Plot actual molecule embeddings in 2D using dimensionality reduction"""
print(f"Encoding {len(smiles_list)} molecules...")
embeddings = self.encode_molecules(smiles_list)
# Create simple labels based on molecular properties
labels = []
for smiles in smiles_list:
mol = Chem.MolFromSmiles(smiles)
if mol is None:
labels.append(0)
else:
# Simple binary classification
mw = Chem.Descriptors.MolWt(mol)
labels.append(1 if mw > 200 else 0)
labels = np.array(labels)
# Reduce dimensionality
print(f"Computing {method.upper()} projection...")
if method == 'tsne':
reducer = TSNE(n_components=2, random_state=42, perplexity=min(30, len(smiles_list)//4))
else:
reducer = PCA(n_components=2, random_state=42)
embeddings_2d = reducer.fit_transform(embeddings)
# Plot
plt.figure(figsize=(10, 8))
scatter = plt.scatter(embeddings_2d[:, 0], embeddings_2d[:, 1],
c=labels, cmap='RdYlGn', alpha=0.7, s=20)
plt.colorbar(scatter, label='Molecular Weight > 200')
plt.title(f'{method.upper()} of Molecule Embeddings - {self.tokenizer.name}')
plt.xlabel(f'{method.upper()} 1')
plt.ylabel(f'{method.upper()} 2')
if save_path:
plt.savefig(save_path, dpi=300, bbox_inches='tight')
plt.show()
def load_data_and_tokenizers():
"""Load data and tokenizers using your existing structure"""
# Load SMILES data (adjust path as needed)
data_path = "../data/sample_all_8k_smi.csv"
if not os.path.exists(data_path):
print(f"Data file not found: {data_path}")
print("Please update the data_path in the script.")
return None, None
df = pd.read_csv(data_path)
if 'SMILES' not in df.columns:
raise ValueError("Expected column 'SMILES' in CSV")
smiles_list = df['SMILES'].dropna().tolist()
# Validate SMILES
valid_smiles = []
for smiles in smiles_list:
if Chem.MolFromSmiles(smiles) is not None:
valid_smiles.append(smiles)
print(f"Loaded {len(valid_smiles)} valid SMILES")
# Initialize tokenizers
try:
tok1_hf = AutoTokenizer.from_pretrained("seyonec/ChemBERTa-zinc-base-v1")
tokenizer1 = TokenizerWrapper(tok1_hf, name="ChemBERTa",
bos_token="<s>", eos_token="</s>",
pad_token="<pad>", unk_token="<unk>")
except Exception as e:
print(f"Failed to load ChemBERTa tokenizer: {e}")
tokenizer1 = None
try:
tok2_fast = FastChemTokenizer.from_pretrained("../smitok")
tokenizer2 = TokenizerWrapper(tok2_fast, name="FastChemTokenizer",
bos_token="[BOS]", eos_token="[EOS]",
pad_token="[PAD]", unk_token="[UNK]")
except Exception as e:
print(f"Failed to load FastChemTokenizer: {e}")
tokenizer2 = None
tokenizers = [t for t in [tokenizer1, tokenizer2] if t is not None]
return valid_smiles, tokenizers
def create_latent_visualizations():
"""Main function to create latent space visualizations"""
# Load data and tokenizers
smiles_list, tokenizers = load_data_and_tokenizers()
if smiles_list is None or not tokenizers:
print("Failed to load data or tokenizers. Please check your setup.")
return
# Use a subset for faster visualization
viz_smiles = smiles_list[:1000] # Adjust size as needed
# Model paths
model_paths = {
'ChemBERTa': './checkpoints/ChemBERTa/best_model_ChemBERTa.pt',
'FastChemTokenizer': './checkpoints/FastChemTokenizer/best_model_FastChemTokenizer.pt'
}
# Create output directory
os.makedirs('latent_space_plots', exist_ok=True)
for tokenizer in tokenizers:
model_path = model_paths.get(tokenizer.name)
if model_path is None or not os.path.exists(model_path):
print(f"Model not found for {tokenizer.name}: {model_path}")
continue
print(f"\n{'='*60}")
print(f"Creating visualizations for {tokenizer.name}")
print(f"{'='*60}")
try:
# Create visualizer
visualizer = LatentSpaceVisualizer(model_path, tokenizer, device)
# Create latent space interpolation plots
print("Creating latent space interpolation plots...")
save_path = f'latent_space_plots/{tokenizer.name}_latent_interpolation.png'
visualizer.plot_latent_space_interpolation(save_path=save_path)
# Create molecule embedding plots
print("Creating t-SNE embedding plot...")
save_path = f'latent_space_plots/{tokenizer.name}_embeddings_tsne.png'
visualizer.plot_molecule_embeddings(viz_smiles, method='tsne', save_path=save_path)
print("Creating PCA embedding plot...")
save_path = f'latent_space_plots/{tokenizer.name}_embeddings_pca.png'
visualizer.plot_molecule_embeddings(viz_smiles, method='pca', save_path=save_path)
except Exception as e:
print(f"Error processing {tokenizer.name}: {str(e)}")
import traceback
traceback.print_exc()
continue
print(f"\n{'='*60}")
print("Visualization complete! Check the 'latent_space_plots' directory for results.")
print(f"{'='*60}")
if __name__ == "__main__":
# Import RDKit descriptors for molecular property calculation
try:
from rdkit.Chem import Descriptors, rdMolDescriptors
except ImportError:
print("RDKit Descriptors not available. Using simpler classification.")
# Fallback to simple classification if descriptors not available
Descriptors = None
rdMolDescriptors = None
create_latent_visualizations()