code: def safe_max_abs(A, ia):
      """Compute np.max(np.abs(A[ia])) possible with empty A."""
      if np.sum(ia):  # ia is not empty
          return np.max(np.abs(A[ia]))
      else:
          return 0.0
  
imports: import functools
  from math import sqrt
  import numpy
  from ..time_frequency._stft import istft, stft, stft_norm1, stft_norm2
  from ..utils import _check_option, _get_blas_funcs, _validate_type, logger, sum_squared, verbose, warn
  from .mxne_debiasing import compute_bias
label_desc: Use image node_id 13 for calling a global function with example usage: safe_max_abs(A, ia) and returns: np, int