ants.apply_transforms(..., compose=...) cannot write hdf5 displacement field. Only nii.gz possible

[MSco]

Is your feature request related to a problem? Please describe.
.nii.gz is a format, that cannot deal with very large data. It would be nice to be able to write hdf5 displacement fields instead of nii.gz. antsApplyTransforms itself makes this possble, but the python wrapper function ants.apply_transforms can only write .nii.gz. It is quite easy to let the developer decide, which kind of displacement field format he would like to create.

Describe the solution you'd like
In ants.apply_transforms, just replace the line

tfn = '%scomptx.nii.gz' % compose if compose is not None else 'NA'

with

if compose:
    tfn = '%scomptx.nii.gz' % compose if not compose.endswith('.h5') else compose
else:
    tfn = 'NA'

Using this solution. The developer can use ants.apply_transforms(..., compose="path/to/my/dispfield.h5") to create an hdf5 displacement field. Using the old code instead, this would just create the following displacement field: "path/to/my/dispfield.h5comptx.nii.gz", which is a .nii.gz.

[stnava]

can you try this , test it and make a pull request?

[MSco]

Tested it successfully and created pull request #476

[cookpa]

Fixed by #476?