Merge pull request #1740 from skoudoro/fix-cvxpy-1.0.15

[FIX] mapmri with cvxpy 1.0.15
dipy · Feb 15, 2019 · 04ddc4e · 04ddc4e
2 parents 818658b + 014b57f
commit 04ddc4e
Showing 1 changed file with 10 additions and 5 deletions.
diff --git a/dipy/reconst/mapmri.py b/dipy/reconst/mapmri.py
@@ -396,10 +396,16 @@ def fit(self, data):
             data_norm = np.asarray(data / data[self.gtab.b0s_mask].mean())
             c = cvxpy.Variable(M.shape[1])
             design_matrix = cvxpy.Constant(M)
-            objective = cvxpy.Minimize(
-                cvxpy.sum_squares(design_matrix * c - data_norm) +
-                lopt * cvxpy.quad_form(c, laplacian_matrix)
-            )
+            # workaround for the bug on cvxpy 1.0.15 when lopt = 0
+            # See https://github.com/cvxgrp/cvxpy/issues/672
+            if not lopt:
+                objective = cvxpy.Minimize(
+                    cvxpy.sum_squares(design_matrix * c - data_norm))
+            else:
+                objective = cvxpy.Minimize(
+                    cvxpy.sum_squares(design_matrix * c - data_norm) +
+                    lopt * cvxpy.quad_form(c, laplacian_matrix)
+                )
             M0 = M[self.gtab.b0s_mask, :]
             constraints = [(M0[0] * c) == 1,
                            (K * c) >= -0.1]
@@ -457,7 +463,6 @@ def __init__(self, model, mapmri_coef, mu, R, lopt, errorcode=0):
             that after positivity constraint failed, also matrix inversion
             failed.
         """
-
         self.model = model
         self._mapmri_coef = mapmri_coef
         self.gtab = model.gtab