icc support for sharp.c / sharp.pyx

[ajvanengelen]

Mat, DW, and I have been experimenting with compiler settings for libsharp. We seem to have found a factor of 2 runtime improvement using icc/ifort rather than gcc/gfort on nersc. In order to take advantage of this, it is necessary to use the same compilers for enlib/sharp and libsharp. Mat has found that this can work if one replaces

enlib/sharp/Makefile

Line 4 in 76c1a7b

$(PYTHON) setup.py build_ext --inplace

with
LDSHARED="icc -shared" CC=icc $(PYTHON) setup.py build_ext --inplace
Could this change get made in the repo version? Could it check if the user is using the intel compiler (based on the contents of $ENLIB_COMP) and insert this if so?

[ajvanengelen]

OK, in my fork I just added this bit to sharp/Makefile that checks whether $CC=icc. Does this look reasonable? I will put in a pull request if so.
https://github.com/ajvanengelen/enlib/blob/d68997745f3e0bb48d39aa0315c48e6e4d684c98/sharp/Makefile#L5

[msyriac]

This issue is solved in the new analysis library: https://github.com/simonsobs/sotools and I will recommend closing it when our transition is complete.