This function performs ALRA (Adaptively-thresholded Low Rank Approximation) imputation
on a gene expression matrix.
     
    
    Usage
    RunALRA(data_mat, k = NULL, q = 0.01, verbose = TRUE)
 
    
    Arguments
- data_mat
- Expression matrix with genes as rows and cells as columns 
- k
- Number of dimensions for SVD (default: NULL, automatically determined) 
- q
- Quantile for automatic k selection (default: 0.01) 
- verbose
- Print progress messages 
 
    
    Value
    Imputed expression matrix