Population_template error: population_template", line 442 TypeError: decode() takes no keyword arguments

1

Hi All,

I have created a fod_input and mask_input directory as recommended in the tutorial to then run population_template.

I get the following error;

File “/midas-data/software/mrtrix3_12.6.18/mrtrix3/bin/population_template”, line 442, in
run.command(‘mraverageheader -fill ’ + ’ ‘.join(input_filenames) + ’ - | mrresize - -voxel ‘+’,’.join(voxel_size)+’ average_header.mif’)
File “/midas-data/software/mrtrix3_12.6.18/mrtrix3/lib/mrtrix3/run.py”, line 197, in command
stderr_text = tempfiles[index][1].read().decode(‘utf-8’, errors=‘replace’)
TypeError: decode() takes no keyword arguments

I can’t figure out what this means or how to solve it. Any advice? (full text bellow) - Many thanks! Paul

population_template …/template/fod_input -mask_dir …/template/mask_input …/template/wmfod_template.mif -voxel_size 1.3
population_template: Generating a population-average template from 40 input images
population_template: SH series detected, performing FOD registration
population_template: initial alignment of images: mass
population_template: linear registration stages:
population_template: (00) rigid scale: 0.3000, niter: 100, lmax: 2
population_template: (01) rigid scale: 0.4000, niter: 100, lmax: 2
population_template: (02) rigid scale: 0.6000, niter: 100, lmax: 2
population_template: (03) rigid scale: 0.8000, niter: 100, lmax: 4
population_template: (04) rigid scale: 1.0000, niter: 100, lmax: 4
population_template: (05) rigid scale: 1.0000, niter: 100, lmax: 4
population_template: (06) affine scale: 0.3000, niter: 500, lmax: 2
population_template: (07) affine scale: 0.4000, niter: 500, lmax: 2
population_template: (08) affine scale: 0.6000, niter: 500, lmax: 2
population_template: (09) affine scale: 0.8000, niter: 500, lmax: 4
population_template: (10) affine scale: 1.0000, niter: 500, lmax: 4
population_template: (11) affine scale: 1.0000, niter: 500, lmax: 4
population_template: nonlinear registration stages:
population_template: (00) nonlinear scale: 0.3000, niter: 5, lmax: 2
population_template: (01) nonlinear scale: 0.4000, niter: 5, lmax: 2
population_template: (02) nonlinear scale: 0.5000, niter: 5, lmax: 2
population_template: (03) nonlinear scale: 0.6000, niter: 5, lmax: 2
population_template: (04) nonlinear scale: 0.7000, niter: 5, lmax: 2
population_template: (05) nonlinear scale: 0.8000, niter: 5, lmax: 2
population_template: (06) nonlinear scale: 0.9000, niter: 5, lmax: 2
population_template: (07) nonlinear scale: 1.0000, niter: 5, lmax: 2
population_template: (08) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (09) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (10) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (11) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (12) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (13) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (14) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: (15) nonlinear scale: 1.0000, niter: 5, lmax: 4
population_template: Generated temporary directory: /media/toshiba/complete/outputs/2012/population_template-tmp-HQSEII/
population_template: Changing to temporary directory (/media/toshiba/complete/outputs/2012/population_template-tmp-HQSEII/)
population_template: Generating initial template
Command: mraverageheader -fill XXX - | mrresize - -voxel 1.3,1.3,1.3 average_header.mif
Traceback (most recent call last):
File “/midas-data/software/mrtrix3_12.6.18/mrtrix3/bin/population_template”, line 442, in
run.command(‘mraverageheader -fill ’ + ’ ‘.join(input_filenames) + ’ - | mrresize - -voxel ‘+’,’.join(voxel_size)+’ average_header.mif’)
File “/midas-data/software/mrtrix3_12.6.18/mrtrix3/lib/mrtrix3/run.py”, line 197, in command
stderr_text = tempfiles[index][1].read().decode(‘utf-8’, errors=‘replace’)
TypeError: decode() takes no keyword arguments

2

Thanks for posting, Paul, that’s potentially really useful information. Just quickly checking, it seems to me that this is related to the changes made in this commit: https://github.com/MRtrix3/mrtrix3/commit/724e91b71b95d185d1e6113909d5a623250b5613#diff-15ea8e46c5e64749b52b4dff228aec59 by Rob. @rsmith, what do you reckon?

3

Thanks Thijs. It might be worth mentioning that I am running on python 2.6.6 which I know is not the 2.7+> that is recommended. If that has anything to do with it.

4

Aha, yes, that seems to be part of the cause indeed. The decode(‘utf-8’, errors=‘replace’) bit doesn’t work on python 2.6: Python 2.6: encode() takes no keyword arguments - Stack Overflow

Coincidentally, other discussions ongoing about this bit: UnicodeDecodeError on .mif headers · Issue #1423 · MRtrix3/mrtrix3 · GitHub

5

Yes, the .decode() call was one of the major factors that led to MRtrix3’s Python requirement being increased to >=2.7. Unfortunately it seems a lot of HPC sysadmins refuse to update beyond 2.6…

While conceivably we could get around this with some Python trickery, 2.6 is exceptionally old, and there’s already a decent amount of gymnastics required to support both Python 2 and 3 in all of our scripts. It would at least be worth checking if the target system has Python3 installed: even an outdated version of Python3 will have the correct syntax.

6

Thanks Rob and Thijs. I have updated my python to 2.7 now and as expected the error does not recur. Looking forward to seeing the template in all its glory!

Best

Paul