******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* I'm just starting to learn Nektar++ from the tutorials and User Guide and mostly it's going very well, but I'm having trouble with FieldConvert -m gradient, hitting a segmentation fault. I'm wondering whether I'm misunderstanding its use. For example, after successfully running the basics-helmholtz example https://doc.nektar.info/tutorials/latest/basics/helmholtz/basics-helmholtz.h... gmsh -2 Helm_mesh.geo Nekmesh Helm_mesh.msh Helm_mesh.xml ADRSolver -v Helm_mesh.xml Helm_conditions.xml FieldConvert Helm_mesh.xml Helm_conditions.xml Helm_mesh.fld Helm_mesh.vtu to produce Helm_mesh.fld and Helm_mesh.vtu, I tried FieldConvert -m gradient Helm_mesh.xml Helm_conditions.xml Helm_mesh.fld Helm-grad.fld following the documentation at https://doc.nektar.info/userguide/latest/user-guidese22.html#x35-1480005.5.1... but this raised [levy:58744] *** Process received signal *** [levy:58744] Signal: Segmentation fault (11) [levy:58744] Signal code: Address not mapped (1) [levy:58744] Failing at address: 0xb0 [levy:58744] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x3f040)[0x7f9d682b1040] [levy:58744] [ 1] /usr/lib/x86_64-linux-gnu/libFieldUtils.so.5.0.0(_ZN6Nektar10FieldUtils11ProcessGrad7ProcessERN5boost15program_options13variables_mapE+0x6cc)[0x7f9d6a1aa7ac] [levy:58744] [ 2] FieldConvert(_Z9RunModuleSt10shared_ptrIN6Nektar10FieldUtils6ModuleEERN5boost15program_options13variables_mapEb+0x3f)[0x55c3dbf99b8f] [levy:58744] [ 3] FieldConvert(main+0x176c)[0x55c3dbf95e5c] [levy:58744] [ 4] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x7f9d68293bf7] [levy:58744] [ 5] FieldConvert(_start+0x2a)[0x55c3dbf9956a] [levy:58744] *** End of error message *** Segmentation fault (core dumped) That's on Ubuntu 18.04, where I had installed nektar++ from http://www.nektar.info/ubuntu-bionic bionic/contrib, but I also get the same error on CentOS 7.7.1908, using the docker image nektarpp/nektar:244f4842. What I was wanting to use the gradient module in my own project fpr was having solved for a steady incompressible potential flow with ADRSolver (EQTYPE "Laplace") to compute the velocity field as the gradient of the potential. Thank you, Geordie McBain Sent from [ProtonMail](https://protonmail.com), Swiss-based encrypted email.