code: def source_extraction(in1, tolerance, mode="cpu", store_on_gpu=False,
                        neg_comp=False):
      
  
      if mode=="cpu":
          return cpu_source_extraction(in1, tolerance, neg_comp)
      elif mode=="gpu":
          return gpu_source_extraction(in1, tolerance, store_on_gpu, neg_comp)
docs: Convenience function for allocating work to cpu or gpu, depending on the selected mode.
  
      INPUTS:
      in1         (no default):   Array containing the wavelet decomposition.
      tolerance   (no default):   Percentage of maximum coefficient at which objects are deemed significant.
      mode        (default="cpu"):Mode of operation - either "gpu" or "cpu".
  
      OUTPUTS:
      Array containing the significant wavelet coefficients of extracted sources.