clean up fourpdm
foundations for disk-based 3-index operators
unique filenames for each op_component
CRE_CRE_CRE build renormalized ops via disk working
out of core renormalization seems to work.  Now need to change npdm driver to read ops from disk, and implement non CRECRECRE 3-index methods
done NPDM lhs-loop read from disk (for CCC op only, easily extended to others)
cleanup
3-index op build parallelism done, but not properly tested.
fixed bugs of duplicate 3-index ops in parallel build, and started stuff for parallelization of 3PDM build loops
started to make generic driver for all npdm builds
generic npdm driver finished
debugged 2-core parallel 2PDM; works with smallest test
memo.txt
2PDM working in parallel with 2 cores
2PDM works with N-cores if lhsOps.size() is not zero in any mpi rank
2PDM seems to work with N-cores in all tests so far
cleaned up calls to npdm build
reworked npdm_driver
more cleanup of driver
general npdm driver implemented up to 4pdm