P. L. Lim pllim

Brian Hayden found performance issue that was reported at astropy/astropy#10548 . Will git bisect identify the offending commit? Reportedly, it was not an issue in 3.2.x but an issue in 4.0.x.

Test script (runme.py) can be something like this and will be in the root directory of the repository checkout:

import time as _time
import numpy as np
from astropy import table

	"""
	Modify the amount of sub-cube you wish to extract in the
	``fits_mmap()`` function. Then run this::

	python measure_memory.py

	My results below. This shows that memory mapping should only
	consume the memory used in accessed sub-cube, not the entire cube.
	Trying to calculate the mean of the entire cube did not work,
	as expected.