Divide by zero during coverage calculation?

[johnstonmj]

Hi Inigo,

While running my samples, I encountered some warnings that I believe come from divide-by-zero during certain coverage calculations.

/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/circlemap/Coverage.py:149: RuntimeWarning: invalid value encountered in ulong_scalars
  start_coverage_ratio = np.sum(region_array[0:self.ilen]) / np.sum(
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/circlemap/Coverage.py:151: RuntimeWarning: invalid value encountered in ulong_scalars
  end_coverage_ratio = np.sum(region_array[-self.ilen:]) / np.sum(ext_array[-(self.ilen + self.ext):])
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/numpy/core/fromnumeric.py:3372: RuntimeWarning: Mean of empty slice.
  return _methods._mean(a, axis=axis, dtype=dtype,
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/numpy/core/_methods.py:170: RuntimeWarning: invalid value encountered in double_scalars
  ret = ret.dtype.type(ret / rcount)
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/numpy/core/_methods.py:233: RuntimeWarning: Degrees of freedom <= 0 for slice
  ret = _var(a, axis=axis, dtype=dtype, out=out, ddof=ddof,
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/numpy/core/_methods.py:194: RuntimeWarning: invalid value encountered in true_divide
  arrmean = um.true_divide(
/home/michael/circles/.snakemake/conda/68e54810/lib/python3.8/site-packages/numpy/core/_methods.py:226: RuntimeWarning: invalid value encountered in double_scalars
  ret = ret.dtype.type(ret / rcount)

The *.circle.bed output is still generated successfully.

Are these warnings expected? Is it safe to ignore them?

Thanks, Michael