app.py

import argparse

import gradio as gr
import numpy as np
import os
import torch
import subprocess
import output

from rdkit import Chem
from src import const
from src.datasets import get_dataloader, collate_with_fragment_edges, parse_molecule
from src.lightning import DDPM
from src.linker_size_lightning import SizeClassifier
from src.generation import N_SAMPLES, generate_linkers, try_to_convert_to_sdf

MODELS_METADATA = {
    'geom_difflinker': {
        'link': 'https://zenodo.org/record/7121300/files/geom_difflinker.ckpt?download=1',
        'path': 'models/geom_difflinker.ckpt',
    },
    'geom_difflinker_given_anchors': {
        'link': 'https://zenodo.org/record/7775568/files/geom_difflinker_given_anchors.ckpt?download=1',
        'path': 'models/geom_difflinker_given_anchors.ckpt',
    },
    'pockets_difflinker': {
        'link': 'https://zenodo.org/record/7775568/files/pockets_difflinker_full_no_anchors.ckpt?download=1',
        'path': 'models/pockets_difflinker.ckpt',
    },
    'pockets_difflinker_given_anchors': {
        'link': 'https://zenodo.org/record/7775568/files/pockets_difflinker_full.ckpt?download=1',
        'path': 'models/pockets_difflinker_given_anchors.ckpt',
    },
}


parser = argparse.ArgumentParser()
parser.add_argument('--ip', type=str, default=None)
args = parser.parse_args()

device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
print(f'Device: {device}')
os.makedirs("results", exist_ok=True)
os.makedirs("models", exist_ok=True)

size_gnn_path = 'models/geom_size_gnn.ckpt'
if not os.path.exists(size_gnn_path):
    print('Downloading SizeGNN model...')
    link = 'https://zenodo.org/record/7121300/files/geom_size_gnn.ckpt?download=1'
    subprocess.run(f'wget {link} -O {size_gnn_path}', shell=True)
size_nn = SizeClassifier.load_from_checkpoint('models/geom_size_gnn.ckpt', map_location=device).eval().to(device)
print('Loaded SizeGNN model')


diffusion_models = {}
for model_name, metadata in MODELS_METADATA.items():
    link = metadata['link']
    diffusion_path = metadata['path']
    if not os.path.exists(diffusion_path):
        print(f'Downloading {model_name}...')
        subprocess.run(f'wget {link} -O {diffusion_path}', shell=True)
    diffusion_models[model_name] = DDPM.load_from_checkpoint(diffusion_path, map_location=device).eval().to(device)
    print(f'Loaded model {model_name}')


print(os.curdir)
print(os.path.abspath(os.curdir))
print(os.listdir(os.curdir))


def read_molecule_content(path):
    with open(path, "r") as f:
        return "".join(f.readlines())


def read_molecule(path):
    if path.endswith('.pdb'):
        return Chem.MolFromPDBFile(path, sanitize=False, removeHs=True)
    elif path.endswith('.mol'):
        return Chem.MolFromMolFile(path, sanitize=False, removeHs=True)
    elif path.endswith('.mol2'):
        return Chem.MolFromMol2File(path, sanitize=False, removeHs=True)
    elif path.endswith('.sdf'):
        return Chem.SDMolSupplier(path, sanitize=False, removeHs=True)[0]
    raise Exception('Unknown file extension')


def show_input(input_file):
    if input_file is None:
        return ['', gr.Radio.update(visible=False, value='Sample 1'), None]
    if isinstance(input_file, str):
        path = input_file
    else:
        path = input_file.name
    extension = path.split('.')[-1]
    if extension not in ['sdf', 'pdb', 'mol', 'mol2']:
        msg = output.INVALID_FORMAT_MSG.format(extension=extension)
        return [
            output.IFRAME_TEMPLATE.format(html=msg),
            gr.Radio.update(visible=False),
            None,
        ]

    try:
        molecule = read_molecule_content(path)
    except Exception as e:
        return [
            f'Could not read the molecule: {e}',
            gr.Radio.update(visible=False),
            None,
        ]

    html = output.INITIAL_RENDERING_TEMPLATE.format(molecule=molecule, fmt=extension)
    return [
        output.IFRAME_TEMPLATE.format(html=html),
        gr.Radio.update(visible=False),
        None,
    ]


def draw_sample(idx, out_files):
    if isinstance(idx, str):
        idx = int(idx.strip().split(' ')[-1]) - 1

    in_file = out_files[0]
    in_sdf = in_file if isinstance(in_file, str) else in_file.name

    out_file = out_files[idx + 1]
    out_sdf = out_file if isinstance(out_file, str) else out_file.name

    input_fragments_content = read_molecule_content(in_sdf)
    generated_molecule_content = read_molecule_content(out_sdf)

    fragments_fmt = in_sdf.split('.')[-1]
    molecule_fmt = out_sdf.split('.')[-1]

    html = output.SAMPLES_RENDERING_TEMPLATE.format(
        fragments=input_fragments_content,
        fragments_fmt=fragments_fmt,
        molecule=generated_molecule_content,
        molecule_fmt=molecule_fmt,
    )
    return output.IFRAME_TEMPLATE.format(html=html)


def generate(input_file, n_steps, n_atoms, radio_samples, selected_atoms):
    # Parsing selected atoms (javascript output)
    selected_atoms = selected_atoms.strip()
    if selected_atoms == '':
        selected_atoms = []
    else:
        selected_atoms = list(map(int, selected_atoms.split(',')))

    # Selecting model
    if len(selected_atoms) == 0:
        selected_model_name = 'geom_difflinker'
    else:
        selected_model_name = 'geom_difflinker_given_anchors'

    if input_file is None:
        return [None, None, None, None]

    print(f'Start generating with model {selected_model_name}, selected_atoms:', selected_atoms)
    ddpm = diffusion_models[selected_model_name]
    path = input_file.name
    extension = path.split('.')[-1]
    if extension not in ['sdf', 'pdb', 'mol', 'mol2']:
        msg = output.INVALID_FORMAT_MSG.format(extension=extension)
        return [output.IFRAME_TEMPLATE.format(html=msg), None, None, None]

    try:
        molecule = read_molecule(path)
        molecule = Chem.RemoveAllHs(molecule)
        name = '.'.join(path.split('/')[-1].split('.')[:-1])
        inp_sdf = f'results/input_{name}.sdf'
    except Exception as e:
        error = f'Could not read the molecule: {e}'
        msg = output.ERROR_FORMAT_MSG.format(message=error)
        return [output.IFRAME_TEMPLATE.format(html=msg), None, None, None]

    if molecule.GetNumAtoms() > 50:
        error = f'Too large molecule: upper limit is 50 heavy atoms'
        msg = output.ERROR_FORMAT_MSG.format(message=error)
        return [output.IFRAME_TEMPLATE.format(html=msg), None, None, None]

    with Chem.SDWriter(inp_sdf) as w:
        w.write(molecule)

    positions, one_hot, charges = parse_molecule(molecule, is_geom=True)
    anchors = np.zeros_like(charges)
    anchors[selected_atoms] = 1

    fragment_mask = np.ones_like(charges)
    linker_mask = np.zeros_like(charges)
    print('Read and parsed molecule')

    dataset = [{
        'uuid': '0',
        'name': '0',
        'positions': torch.tensor(positions, dtype=const.TORCH_FLOAT, device=device),
        'one_hot': torch.tensor(one_hot, dtype=const.TORCH_FLOAT, device=device),
        'charges': torch.tensor(charges, dtype=const.TORCH_FLOAT, device=device),
        'anchors': torch.tensor(anchors, dtype=const.TORCH_FLOAT, device=device),
        'fragment_mask': torch.tensor(fragment_mask, dtype=const.TORCH_FLOAT, device=device),
        'linker_mask': torch.tensor(linker_mask, dtype=const.TORCH_FLOAT, device=device),
        'num_atoms': len(positions),
    }] * N_SAMPLES
    dataloader = get_dataloader(dataset, batch_size=N_SAMPLES, collate_fn=collate_with_fragment_edges)
    print('Created dataloader')

    ddpm.edm.T = n_steps

    if n_atoms == 0:
        def sample_fn(_data):
            out, _ = size_nn.forward(_data, return_loss=False)
            probabilities = torch.softmax(out, dim=1)
            distribution = torch.distributions.Categorical(probs=probabilities)
            samples = distribution.sample()
            sizes = []
            for label in samples.detach().cpu().numpy():
                sizes.append(size_nn.linker_id2size[label])
            sizes = torch.tensor(sizes, device=samples.device, dtype=torch.long)
            return sizes
    else:
        def sample_fn(_data):
            return torch.ones(_data['positions'].shape[0], device=device, dtype=torch.long) * n_atoms

    for data in dataloader:
        try:
            generate_linkers(ddpm=ddpm, data=data, sample_fn=sample_fn, name=name)
        except Exception as e:
            error = f'Caught exception while generating linkers: {e}'
            msg = output.ERROR_FORMAT_MSG.format(message=error)
            return [output.IFRAME_TEMPLATE.format(html=msg), None, None, None]

    out_files = try_to_convert_to_sdf(name)
    out_files = [inp_sdf] + out_files

    return [
        draw_sample(radio_samples, out_files),
        out_files,
        gr.Radio.update(visible=True),
        None
    ]


demo = gr.Blocks()
with demo:
    gr.Markdown('# DiffLinker: Equivariant 3D-Conditional Diffusion Model for Molecular Linker Design')
    gr.Markdown(
        'Given a set of disconnected fragments in 3D, '
        'DiffLinker places missing atoms in between and designs a molecule incorporating all the initial fragments. '
        'Our method can link an arbitrary number of fragments, requires no information on the attachment atoms '
        'and linker size, and can be conditioned on the protein pockets.'
    )
    gr.Markdown(
        '[**[Paper]**](https://arxiv.org/abs/2210.05274)    '
        '[**[Code]**](https://github.com/igashov/DiffLinker)'
    )
    with gr.Box():
        with gr.Row():
            hidden = gr.Textbox(visible=False)
            with gr.Column():
                gr.Markdown('## Input Fragments')
                gr.Markdown('Upload the file with 3D-coordinates of the input fragments in .pdb, .mol2 or .sdf format:')
                input_file = gr.File(file_count='single', label='Input Fragments')
                n_steps = gr.Slider(minimum=10, maximum=500, label="Number of Denoising Steps", step=10)
                n_atoms = gr.Slider(
                    minimum=0, maximum=20,
                    label="Linker Size: DiffLinker will predict it if set to 0",
                    step=1
                )
                examples = gr.Dataset(
                    components=[gr.File(visible=False)],
                    samples=[['examples/example_1.sdf'], ['examples/example_2.sdf']],
                    type='index',
                ) 

                button = gr.Button('Generate Linker!')
                gr.Markdown('')
                gr.Markdown('## Output Files')
                gr.Markdown('Download files with the generated molecules here:')
                output_files = gr.File(file_count='multiple', label='Output Files', interactive=False)
            with gr.Column():
                gr.Markdown('## Visualization')
                gr.Markdown('**Hint:** click on atoms to select anchor points (optionally)')
                samples = gr.Radio(
                    choices=['Sample 1', 'Sample 2', 'Sample 3', 'Sample 4', 'Sample 5'],
                    value='Sample 1',
                    type='value',
                    show_label=False,
                    visible=False,
                    interactive=True,
                )
                visualization = gr.HTML()

    input_file.change(
        fn=show_input,
        inputs=[input_file],
        outputs=[visualization, samples, hidden],
    )
    input_file.clear(
        fn=lambda: [None, '', gr.Radio.update(visible=False), None],
        inputs=[],
        outputs=[input_file, visualization, samples, hidden],
    )
    examples.click(
        fn=lambda idx: [f'examples/example_{idx+1}.sdf', 10, 0] + show_input(f'examples/example_{idx+1}.sdf'),
        inputs=[examples],
        outputs=[input_file, n_steps, n_atoms, visualization, samples, hidden]
    )
    button.click(
        fn=generate,
        inputs=[input_file, n_steps, n_atoms, samples, hidden],
        outputs=[visualization, output_files, samples, hidden],
        _js=output.RETURN_SELECTION_JS,
    )
    samples.change(
        fn=draw_sample,
        inputs=[samples, output_files],
        outputs=[visualization],
    )
    demo.load(_js=output.STARTUP_JS)

demo.launch(server_name=args.ip)