remove openmp sections in factorization

4 jobs for master in 8 minutes and 20 seconds (queued for 1 minute)
Status Job ID Name Coverage
  Build
passed #1071
build_debug

00:02:47

passed #1072
build_opt

00:04:01

 
  Test
passed #1073
test_debug

00:01:01

passed #1074
test_opt

00:00:30