Add mdr keyword to T1() class

ukat/mapping/t1.py

@@ -3,6 +3,8 @@
 import os
 import warnings
 
+import mdreg
+
 from . import fitting
 
 
@@ -148,8 +150,11 @@ class T1:
         apart from TI
     """
 
+    #@Alex: suggestion: make affine a keyword parameter with default np.eye(4).
+    # As it is the last argument in the list this will not break existing code
+    # And it means the user is not forced to provide a dummy affine when it plays no role.
     def __init__(self, pixel_array, inversion_list, affine, tss=0, tss_axis=-2,
-                 mask=None, parameters=2, molli=False, multithread=True):
+                 mask=None, parameters=2, molli=False, multithread=True, mdr=False):
         """Initialise a T1 class instance.
 
         Parameters
@@ -201,12 +206,71 @@ def __init__(self, pixel_array, inversion_list, affine, tss=0, tss_axis=-2,
             increase in speed distributing the calculation would generate.
             'auto' attempts to apply multithreading where appropriate based
             on the number of voxels being fit.
+        mdr : bool, optional
+            Default 'False`
+            If True, this performs a motion correction with model-driven 
+            registration before performing the final fit to the model function. 
         """
+
         assert multithread is True \
                or multithread is False \
                or multithread == 'auto', f'multithreaded must be True,' \
                                          f'False or auto. You entered ' \
                                          f'{multithread}'
+
+        # @Alex: I have moved this up so multithreading 
+        # settings can be reused in mdreg, which requires a True or False
+        # value. In this case (elastix) it is actually unnecessary as 
+        # parallelization is not a real option anyway. But it would be relevant if 
+        # wanted to run with skimage, for instamce.
+        if multithread == 'auto':
+            npixels = np.prod(pixel_array.shape[:-1])
+            if npixels > 20:
+                multithread = True
+            else:
+                multithread = False
+
+        if mdr:
+            pixel_array, deform, _, _ = mdreg.fit(
+                pixel_array, 
+                fit_image = {
+                    'func': _T1_fit,
+                    'inversion_list': inversion_list,
+                    'affine': affine,
+                    'tss': tss, 
+                    'tss_axis': tss_axis,
+                    'mask': mask, 
+                    'parameters': parameters, 
+                    'molli': molli, 
+                    'multithread': multithread, 
+                },
+                # @Alex: These coreg settings are default so technically speaking do not have 
+                # to be specified here. I am leaving it in nevertheless as a template in case we want
+                # to explore alternative coregistration settings later. The fit_coreg
+                # dictionary could also be exposed as a keyword argument in T1.__init__() 
+                # in case we want to give the user the option to modify the detail. 
+                # As it stands the user has no way of modifying the way mdr runs, eg. 
+                # change verbosity level, stopping criteria or coreg options. 
+                # I didn't change it as that may exactly be the intention of ukat? 
+                fit_coreg = {
+                    'package': 'elastix',
+                    'parallel': False, # elastix is not parallelizable
+                }
+            )
+            # @Alex: At the moment the order of the dimensions in the deformation field returned by mdreg is awkward.
+            # Current dimensions are (x,y,2,t) for 2-dimensional pixel_arrays, 
+            # and (x,y,z,3,t) for 3 dimensional. Better would be (x,y,t,2) and (x,y,z,t,3) 
+            # - i.e add a new dimension at the end.
+            # We will probable change this in mdreg at some point so I put in an ad-hoc
+            # reordering at this stage, We can just take it out later if mdreg is updated.
+            self.deformation_field = np.swapaxes(deform, -2, -1)
+            # @Alex: Hack to avoid magnitude corrected model being selected
+            # This needs a better solution as this prevents a magnitude corrected mode
+            pixel_array = np.abs(pixel_array)
+        else:
+            # @Alex: is this the expected default?
+            self.deformation_field = None
+
 
         self.pixel_array = pixel_array
         self.shape = pixel_array.shape[:-1]
@@ -230,11 +294,6 @@ def __init__(self, pixel_array, inversion_list, affine, tss=0, tss_axis=-2,
             self.tss = 0
         self.parameters = parameters
         self.molli = molli
-        if multithread == 'auto':
-            if self.n_vox > 20:
-                multithread = True
-            else:
-                multithread = False
         self.multithread = multithread
 
         # Some sanity checks
@@ -556,3 +615,11 @@ def magnitude_correct(pixel_array):
     sign = -(phase_offset / np.abs(phase_offset))
     corrected_array = sign * np.abs(pixel_array)
     return corrected_array
+
+
+# Private wrapper for use by mdreg
+def _T1_fit(pixel_array, inversion_list=None, affine=None, **kwargs):
+    # Alex: added the abs() here to avoid the bug with model selection
+    # This needs a better solution as this prevents a magnitude corrected mode
+    map = T1(np.abs(pixel_array), inversion_list, affine, **kwargs)
+    return map.get_fit_signal(), None