3d compatibility sparsity

proxtoolbox/ProxOperators/P_Sparsity.py

@@ -27,7 +27,7 @@ class P_Sparsity(ProxOperator):
         else:
             self.support = 1
 
-        if self.sparsity_parameter > 30:
+        if self.sparsity_parameter > 30 or len(config['u0'].shape) != 2:
             def value_selection(original, indices, sparsity_parameter):
                 idx_for_threshold = unravel_index(indices[-sparsity_parameter], original.shape)
                 threshold_val = abs(original[idx_for_threshold].get())