TypeError: Cannot cast ufunc multiply output from dtype('float64') to dtype('<i2') with casting rule 'same_kind'

[jdkent]

I generated the following error using fieldmaps from a GE scanner which had one fieldmap (in Hz) and a magnitude image. The error I received appears to be similar to numpy/numpy#7225.

Command

docker run --rm  \
-v /Users/jdkent/dev_env/test_data2:/data:ro \
-v /Users/jdkent/dev_env/test_data2/derivatives_fieldmap_dev:/out \
poldracklab/fmriprep:latest /data /out participant \
--participant_label GE161 -w /out/work \
--nthreads 16 --omp-nthreads 16 --mem_mb 21000 \
--no-freesurfer --write-graph --debug --template MNI152NLin2009cAsym

ERROR

170616-18:07:40,708 workflow ERROR:
	 ['Node torads failed to run on host 17e760022550.']
170616-18:07:40,714 workflow INFO:
	 Saving crash info to /out/fmriprep/sub-GE161/log/20170616-180438_5f900bfa-47e8-4ccb-8bef-68a59df983c6/crash-20170616-180740-root-torads-db37a3ce-e9fb-4ca8-8040-91463b4d8e05.pklz
170616-18:07:40,715 workflow INFO:
	 Traceback (most recent call last):
  File "/usr/local/miniconda/lib/python3.6/site-packages/nipype/pipeline/plugins/multiproc.py", line 52, in run_node
    result['result'] = node.run(updatehash=updatehash)
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/pipeline/engine/nodes.py", line 372, in run
    self._run_interface()
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/pipeline/engine/nodes.py", line 482, in _run_interface
    self._result = self._run_command(execute)
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/pipeline/engine/nodes.py", line 613, in _run_command
    result = self._interface.run()
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/interfaces/base.py", line 1083, in run
    runtime = self._run_wrapper(runtime)
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/interfaces/base.py", line 1031, in _run_wrapper
    runtime = self._run_interface(runtime)
  File "/usr/local/miniconda/lib/python3.6/site-packages/niworkflows/nipype/interfaces/utility/wrappers.py", line 192, in _run_interface
    out = function_handle(**args)
  File "<string>", line 13, in _torads
TypeError: Cannot cast ufunc multiply output from dtype('float64') to dtype('<i2') with casting rule 'same_kind'
Interface Function failed to run. 

My fix:
fmapdata *= (pi / cutoff) becomes fmapdata = fmapdata * (pi / cutoff)

fmapdata *= (cutoff_hz / pi) becomes fmapdata = fmapdata * (cutoff_hz / pi)

Not as pretty as *=, but the fix works for me.

Let me know if you need more details/access to files.

Side question: how would I submit this as a pull request while I'm still working on ICA_AROMA on my fork, do I need to make another branch from my fork, do a hard reset with the poldrack/fmriprep master branch (to get rid of the ICA_AROMA changes), make my change and then create a new pull request from that branch?

[chrisgorgo]

You can do:

git checkout 7192829
git checkout -b fix/fieldmaps

Commit your changes there and push them to your repo. Then open a PR. In the future it's better not to make any commits to master and use branches for fixes and features.