# scvelo.pp.moments¶

scvelo.pp.moments(data, n_neighbors=30, n_pcs=None, mode='connectivities', method='umap', use_rep=None, use_highly_variable=True, copy=False)

Computes moments for velocity estimation.

First-/second-order moments are computed for each cell across its nearest neighbors, where the neighbor graph is obtained from euclidean distances in PCA space.

Parameters: data : AnnData Annotated data matrix. n_neighbors : int (default: 30) Number of neighbors to use. n_pcs : int (default: None) Number of principal components to use. If not specified, the full space is used of a pre-computed PCA, or 30 components are used when PCA is computed internally. mode : ‘connectivities’ or ‘distances’ (default: ‘connectivities’) Distance metric to use for moment computation. method : {{‘umap’, ‘hnsw’, ‘sklearn’, None}} (default: ‘umap’) Method to compute neighbors, only differs in runtime. Connectivities are computed with adaptive kernel width as proposed in Haghverdi et al. 2016 (https://doi.org/10.1038/nmeth.3971). use_rep : None, ‘X’ or any key for .obsm (default: None) Use the indicated representation. If None, the representation is chosen automatically: for .n_vars < 50, .X is used, otherwise ‘X_pca’ is used. use_highly_variable : bool (default: True) Whether to use highly variable genes only, stored in .var[‘highly_variable’]. copy : bool (default: False) Return a copy instead of writing to adata. Ms (.layers) – dense matrix with first order moments of spliced counts. Mu (.layers) – dense matrix with first order moments of unspliced counts.