SCOIT

SCOIT is an implementation of a probabilistic tensor decomposition framework for single-cell multiomic data integration. SCOIT accepts the input of datasets from multiple omics, with missing values allowed.

Getting started

Prerequisite

• numpy
• scipy 1.6.0
• sklearn
• communities
• igraph
• leidenalg
• pytorch 1.9.0

Install

pip install SCOIT

Examples

We put the complete scripts for the analysis described in the manuscript under examples/ directory for detailed usage examples and reproduction. The example data can be downloaded from Google Drive.

This is an example of multiple datasets when features have corresponding information.

from scoit import sc_multi_omics

data = np.array([expression_data, methylation_data])
sc_model = sc_multi_omics()
predict_data = sc_model.fit(data) # the imputed data
np.savetxt("global_cell_embeddings.csv", sc_model.C, delimiter = ',') # global cell embeddings
np.savetxt("global_gene_embeddings.csv", sc_model.G, delimiter = ',') # global gene embeddings
np.savetxt("local_cell_embeddings.csv", sc_model.C, delimiter = ',') # omics-specific cell embeddings
np.savetxt("local_gene_embeddings.csv", sc_model.G, delimiter = ',') # omics-specific gene embeddings

# imputation
imputed_expression_data = predict_data[0]
imputed_methylation_data = predict_data[1]

When the features of different omics do not have corresponding information, please use the fit_list function, which accepts the input as a list of matrices.

from scoit import sc_multi_omics

data = [expression_data, protein_data]
sc_model = sc_multi_omics()
predict_data = sc_model.fit_list(data)

If the input does not contain missing values ("NA"), we provide fit_complete and fit_list_complete functions to accelerate the optimization since they take advantage of matrix operations.

from scoit import sc_multi_omics

data = np.array([expression_data, methylation_data])
sc_model = sc_multi_omics()
predict_data = sc_model.fit_complete(data) # the imputed data

from scoit import sc_multi_omics

data = [expression_data, protein_data]
sc_model = sc_multi_omics()
predict_data = sc_model.fit_list_complete(data)

Parameters

sc_multi_omics

• K1: The local element-wise product parameter, see the manuscript for details (default=30).
• K2: The local element-wise product parameter (default=30).
• K3: The local element-wise product parameter (default=30).
• random_seed: The random seed used in optimization (default=123).

fit

• normalization: Whether to applied min-max normalization (default=True).
• pre_impute: Whether to applied KNNImputer for pre-processing (default=False).
• opt: The optimization algorithm for gradient descent, including SGD, Adam, Adadelta, Adagrad, AdamW, SparseAdam, Adamax, ASGD, LBFGS (default="Adam").
• dist:The distribution used for modeling, including gaussian, poisson, negative_bionomial (default="gaussian").
• lr: The learning rate for gradient descent (default=1e-2).
• n_epochs: The number of optimization epochs (default=1000).
• lambda_C_regularizer: The coefficient for the penalty term of global cell embeddings (default=0, indicating automatically adjust.).
• lambda_G_regularizer: The coefficient for the penalty term of global gene embeddings (default=0).
• lambda_O_regularizer: The coefficient list for the penalty term of global omics embeddings; the length of the list should be the same with the number of omics (default=[0, 0]).
• lambda_OC_regularizer: The coefficient list for the penalty term of omics-specific cell embeddings; the length of the list should be the same with the number of omics, not avaiable for complete functions (default=[0, 0]).
• lambda_OG_regularizer: The coefficient list for the penalty term of omics-specific gene embeddings, the length of the list should be the same with the number of omics, not avaiable for list functions (default=[0, 0]).
• batch_size: The batch size used for gradient descent, not avaiable for complete functions (default=256).
• device: CPU or GPU (default='cuda' if torch.cuda.is_available() else 'cpu').
• verbose: Whether to print loss for each epoch (default=True).

cell_analysis

knn_adj_matrix

Construct KNN graph with the cell embeddings.

• k: The number of neighbos used to construct KNN graph (default=20).

snn_adj_matrix

Construct SNN graph with the cell embeddings.

• k: The number of neighbos used to construct SNN graph (default=20).

jsnn_adj_matrix

Construct jSNN graph with the cell embeddings.

• k: The number of neighbos used to construct jaccard SNN graph (default=20).
• prune: Set the score below the value to zero (default=1/15).

RunLouvain

Run Louvain algorithm for the graph.

• k: Terminate the search once this number of communities is detected (default=None).

RunSpectral

Run Spectral clustering algorithm for the graph.

• k: Number of clusters (default=5).

RunLeiden

Run Leiden algorithm for the graph.

gene_analysis

pearson_correlation

Calculate the correlation between the features.

feature_projection

Project the feature embedding to cell embeddings and visualize with UMAP.

• umap_epochs: The number of UMAP epochs for visualization (default=100).
• dimension: The dimension of the embeddings to use (default=30).
• figure_name: The saved figure name (default="feature_projections.png").

Version history

• v0.1.2: Adjust correlation calculation.
• v0.1.1: Automatically adjusts the coefficients; Add downstream analyses; Extend to unpaired data.
• v0.0.1: Initial version.

Maintainer

WANG Ruohan ruohawang2-c@my.cityu.edu.hk