Memory usage issue

[V-Rang]

commit: 9906551

Investigating memory usage issue which might be causing the hanging of the testing_suite_file.py after 3 out of the 4 tests are run: https://github.com/hippylib/hippylibx/blob/numpy_debug_v2/hippylibX/test/testing_suite_file.py

Ran mem_usage.py: https://github.com/hippylib/hippylibx/blob/numpy_debug_v2/misc/mem_usage.py
to generate this plot:

This documents the change in memory used from one iteration to another. (difference between memory being used at end and beginning of function call).

Have noticed that if all 4 tests in testing_suite_file.py are called using 1 proc, it runs to completion.