Strange... Can you provide information about what OS you're running on? Also, what version of MRtrix3 (
dwidenoise -version)? And some information about the input image might be useful - in particular if it's large: it looks like
malloc() is failing to allocate a chunk of ~625 petabytes, which is not surprising, but we'd need to figure out why it tries to do this in the first place...
Also, what is the full output when running with the
-debug command? This will give us an idea of which step is failing. Also, can you try running without multi-threading (
-nthread 0) to see whether the issue relates to concurrency. And if you have time and the inclination, can you try running this within the debugger:
gdb --args dwidenoise dwi.mif denoised.mif -noise noise.mif -force -debug -nthread 0
[ allow program to run & crash ]
And post the full output of that run.
Also, you mention that this command works OK the first time? So is this an intermittent problem? If so, I would suspect some issue with your system rather than MRtrix per se. One possible issue is that you might have performed a system software update recently, but not rebooted, which might lead to instabilities due to mismatches between the (old) running kernel and the updated system libraries, or issues of that nature.
Not sure about the second problem with
mrview, but given your issues with
dwidenoise, I strongly suspect fixing one will fix the other...