code: def Channel_Swap(
      matrix, escape_attempts=0, verbosity=0, permutation=None
  ):
      threshold = 0.00001
      used_escape_attempts = 0
  
      # initialize
      if permutation is None:
          permutation = [c for c in range(matrix.shape[1])]
      swap_map = []
      swap_ids = []
      used_stripes = []
      swap_count = 0
      iterations = 0
      agg_improvement = 0.0
      cur_total_sum = sum_after_2_to_4(matrix)
      start_time = time.perf_counter()
  
      # do the work
      swapped = 1  # just start with nonzero value to fall into the loop
      while swapped > 0:
          swap_map, swap_ids = build_swap_map(
              matrix, swap_map, swap_ids, used_stripes, verbosity
          )
          (
              matrix,
              swapped,
              swap_map,
              swap_ids,
              used_stripes,
              improvement,
              used_escape_attempts,
              permutation,
          ) = use_swap_map(
              matrix,
              swap_map,
              swap_ids,
              threshold,
              used_escape_attempts,
              escape_attempts,
              permutation,
              verbosity,
          )
          agg_improvement += improvement
  
          # keep track of statistics, print occasionally
          swap_count += swapped
          if verbosity > 10:
              iterations += 1
              cur_total_sum += agg_improvement
              duration = time.perf_counter() - start_time
              print(
                  f"\t{iterations:8} {cur_total_sum:7.2f} {agg_improvement:7.2f} {swap_count:4} {agg_improvement/max(swap_count,1):5.2f} {duration:7.2f}"
              )
              agg_improvement = 0.0
              swap_count = 0
  
      # final status
      seconds = time.perf_counter() - start_time
  
      return matrix, seconds, permutation
  
file_path: apex/apex/contrib/sparsity/permutation_search_kernels/channel_swap.py
imports: from .permutation_utilities import *
label_desc: Use image node_id 8 for calling a global function with example usage: Channel_Swap(matrix, escape_attempts, verbosity, permutation) and returns: matrix,  seconds,  permutation