lisaac nbody -q -O -i20
gcc nbody_c.c -o nbody_c -O3 -fomit-frame-pointer -lm
echo Lisaac: 
time ./nbody 20000000 > out_li.txt
# time ./nbody 1 > out_li.txt
echo C:
time ./nbody_c 20000000 > out_c.txt
# time ./nbody_c 1 > out_c.txt
diff out_li.txt out_c.txt
