SkyModelGradientOperator -> ModelGradientOperator

nifty5/models/constant.py

-from ..operators import MultiSkyGradientOperator
+from ..operators.model_gradient_operator import ModelGradientOperator
 from .model import Model
 
 
@@ -9,8 +9,7 @@ class Constant(Model):
 
         self._value = self._constant
 
-        self._gradient = MultiSkyGradientOperator({},
-                                                  position.domain,
+        self._gradient = ModelGradientOperator({}, position.domain,
                                                self.value.domain)
 
     def at(self, position):

nifty5/operators/__init__.py

@@ -12,7 +12,7 @@ from .power_distributor import PowerDistributor
 from .sampling_enabler import SamplingEnabler
 from .sandwich_operator import SandwichOperator
 from .scaling_operator import ScalingOperator
-from .sky_gradient_operator import MultiSkyGradientOperator
+from .model_gradient_operator import ModelGradientOperator
 from .smoothness_operator import SmoothnessOperator
 
 __all__ = ["LinearOperator", "EndomorphicOperator", "ScalingOperator",
@@ -20,4 +20,4 @@ __all__ = ["LinearOperator", "EndomorphicOperator", "ScalingOperator",
            "FFTSmoothingOperator", "GeometryRemover",
            "LaplaceOperator", "SmoothnessOperator", "PowerDistributor",
            "InversionEnabler", "SandwichOperator", "SamplingEnabler",
-           "DOFDistributor", "MultiSkyGradientOperator"]
+           "DOFDistributor", "ModelGradientOperator"]

nifty5/operators/sky_gradient_operator.py → nifty5/operators/model_gradient_operator.py

-from ..multi import MultiDomain, MultiField
+from ..multi.multi_domain import MultiDomain
+from ..multi.multi_field import MultiField
 from ..sugar import full
 from .linear_operator import LinearOperator
 
 
-class MultiSkyGradientOperator(LinearOperator):
+class ModelGradientOperator(LinearOperator):
     def __init__(self, gradients, domain, target):
-        super(MultiSkyGradientOperator, self).__init__()
+        super(ModelGradientOperator, self).__init__()
         self._gradients = gradients
         gradients_domain = MultiField(self._gradients).domain
         self._domain = MultiDomain.make(domain)