MRtrix3 provides a set of tools to perform various advanced diffusion MRI analyses, including constrained spherical deconvolution (CSD), probabilistic tractography, track-density imaging, and apparent fibre density
This looks like an issue with an incorrectly configured FSL install - newer versions need to be handled differently. See this discussion on the forum for details.
Hi experts, I tried to install the Mrtrix3 on ubuntu 18 but failed. Any suggestions are appreciated. Thanks, Yawu configure.log