Spaces and FieldTypes now support pre_cast and post_cast.

-> A Field on a PowerSpace can now be initialized with a spectral function.

nifty/field.py

@@ -490,14 +490,22 @@ class Field(object):
         else:
             dtype = np.dtype(dtype)
 
-        casted_x = self._actual_cast(x, dtype=dtype)
+        for ind, sp in enumerate(self.domain):
+            casted_x = sp.pre_cast(x,
+                                   axes=self.domain_axes[ind])
+
+        for ind, ft in enumerate(self.field_type):
+            casted_x = ft.pre_cast(casted_x,
+                                   axes=self.field_type_axes[ind])
+
+        casted_x = self._actual_cast(casted_x, dtype=dtype)
 
         for ind, sp in enumerate(self.domain):
-            casted_x = sp.complement_cast(casted_x,
+            casted_x = sp.post_cast(casted_x,
                                     axes=self.domain_axes[ind])
 
         for ind, ft in enumerate(self.field_type):
-            casted_x = ft.complement_cast(casted_x,
+            casted_x = ft.post_cast(casted_x,
                                     axes=self.field_type_axes[ind])
 
         return casted_x

nifty/field_types/field_type.py

@@ -51,5 +51,8 @@ class FieldType(object):
 
         return result_array
 
-    def complement_cast(self, x, axes=None):
+    def pre_cast(self, x, axes=None):
+        return x
+
+    def post_cast(self, x, axes=None):
         return x

nifty/spaces/power_space/power_space.py

@@ -14,7 +14,8 @@ class PowerSpace(Space):
 
     # ---Overwritten properties and methods---
 
-    def __init__(self, harmonic_domain=RGSpace((1,)), distribution_strategy='not',
+    def __init__(self, harmonic_domain=RGSpace((1,)),
+                 distribution_strategy='not',
                  log=False, nbin=None, binbounds=None,
                  dtype=np.dtype('float')):
 
@@ -51,6 +52,12 @@ class PowerSpace(Space):
         raise NotImplementedError(about._errors.cstring(
             "ERROR: There is no k_array implementation for PowerSpace."))
 
+    def pre_cast(self, x, axes=None):
+        if callable(x):
+            return x(self.kindex)
+        else:
+            return x
+
     # ---Mandatory properties and methods---
 
     @property

nifty/spaces/space/space.py

@@ -266,7 +266,10 @@ class Space(object):
         """
         raise NotImplementedError
 
-    def complement_cast(self, x, axes=None):
+    def pre_cast(self, x, axes=None):
+        return x
+
+    def post_cast(self, x, axes=None):
         return x
 
     def compute_k_array(self, distribution_strategy):