Added nonlinear tests for FSL

Author: smoia

nitransforms/nonlinear.py

@@ -77,14 +77,15 @@ def map(self, x, inverse=False):
 
     @classmethod
     def from_filename(cls, filename, fmt="X5"):
-        if fmt == "afni":
-            _factory = io.afni.AFNIDisplacementsField
-        elif fmt == "itk":
-            _factory = io.itk.ITKDisplacementsField
-        else:
-            raise NotImplementedError
-
-        return cls(_factory.from_filename(filename))
+        _factory = {
+            "afni": io.afni.AFNIDisplacementsField,
+            "itk": io.itk.ITKDisplacementsField,
+            "fsl": io.fsl.FSLDisplacementsField,
+        }
+        if fmt not in _factory:
+            raise NotImplementedError(f"Unsupported format <{fmt}>")
+
+        return cls(_factory[fmt].from_filename(filename))
 
 
 load = DisplacementsFieldTransform.from_filename

nitransforms/tests/test_nonlinear.py

@@ -12,6 +12,7 @@
 from ..nonlinear import DisplacementsFieldTransform, load as nlload
 from ..io.itk import ITKDisplacementsField
 
+
 TESTS_BORDER_TOLERANCE = 0.05
 APPLY_NONLINEAR_CMD = {
     "itk": """\
@@ -22,6 +23,9 @@
 3dNwarpApply -nwarp {transform} -source {moving} \
 -master {reference} -interp NN -prefix resampled.nii.gz
 """.format,
+    'fsl': """\
+applywarp -i {moving} -r {reference} -o resampled.nii.gz \
+-w {transform} --interp=nn""".format,
 }