The `smooth()` function crash

[algebrato]

When the smooth fuction is activated, the atmospheri simulation return a segmentation fault:

[guendalf:11313] *** Process received signal ***
[guendalf:11313] Signal: Segmentation fault (11)
[guendalf:11313] Signal code: Address not mapped (1)
[guendalf:11313] Failing at address: 0xa78c
[guendalf:11313] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x3b800)[0x7f50f303a800]
[guendalf:11313] [ 1] /home/algebrato/.local/lib/python3.8/site-packages/pycal/_libcal_mpi.cpython-38-x86_64-linux-gnu.so(+0x1aa3ec)[0x7f50ec4493ec]
[guendalf:11313] [ 2] /usr/lib/x86_64-linux-gnu/libgomp.so.1(+0x19de6)[0x7f50ec278de6]
[guendalf:11313] [ 3] /lib/x86_64-linux-gnu/libpthread.so.0(+0x8f27)[0x7f50f2fe6f27]
[guendalf:11313] [ 4] /lib/x86_64-linux-gnu/libc.so.6(clone+0x3f)[0x7f50f30fc31f]
[guendalf:11313] *** End of error message ***