corrected pipline errors

6 jobs for feature/interpolation in 51 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
canceled #7433
debian:10 clang-6-libcpp-17

00:00:51

canceled #7432
debian:10 gcc-8-noassert-17

00:00:51

canceled #7435
debian:9 clang-3.8-14

canceled #7434
debian:9 gcc-6-14

00:00:03

canceled #7436
ubuntu:16.04 gcc-5-14

canceled #7437
ubuntu:18.04 clang-6-17