ENH: remove Operator parent class from FunctionSpaceElement, closes #949

odl/operator/operator.py

@@ -73,46 +73,39 @@ def _default_call_in_place(op, x, out, **kwargs):
     out.assign(op.range.element(op._call_out_of_place(x, **kwargs)))
 
 
-def _signature_from_spec(func):
-    """Return the signature of a python function as a string.
+def _get_signature(func):
+    """Return the signature of a callable as a string.
 
     Parameters
     ----------
-    func : `function`
-        Function whose signature to compile
+    func : callable
+        Function whose signature to extract.
 
     Returns
     -------
     sig : string
-        Signature of the function
+        Signature of the function.
     """
-    py3 = (sys.version_info.major > 2)
-    if py3:
-        spec = inspect.getfullargspec(func)
-    else:
-        spec = inspect.getargspec(func)
+    if sys.version_info.major > 2:
+        # Python 3 already implements this functionality
+        return func.__name__ + str(inspect.signature(func))
 
+    # In Python 2 we have to do it manually, unfortunately
+    spec = inspect.getargspec(func)
     posargs = spec.args
     defaults = spec.defaults if spec.defaults is not None else []
     varargs = spec.varargs
-    kwargs = spec.varkw if py3 else spec.keywords
+    kwargs = spec.keywords
     deflen = 0 if defaults is None else len(defaults)
     nodeflen = 0 if posargs is None else len(posargs) - deflen
 
     args = ['{}'.format(arg) for arg in posargs[:nodeflen]]
-    args += ['{}={}'.format(arg, dval)
-             for arg, dval in zip(posargs[nodeflen:], defaults)]
+    args.extend('{}={}'.format(arg, dval)
+                for arg, dval in zip(posargs[nodeflen:], defaults))
     if varargs:
-        args += ['*{}'.format(varargs)]
-    if py3:
-        kw_only = spec.kwonlyargs
-        kw_only_defaults = spec.kwonlydefaults
-        if kw_only and not varargs:
-            args += ['*']
-        args += ['{}={}'.format(arg, kw_only_defaults[arg])
-                 for arg in kw_only]
+        args.append('*{}'.format(varargs))
     if kwargs:
-        args += ['**{}'.format(kwargs)]
+        args.append('**{}'.format(kwargs))
 
     argstr = ', '.join(args)
 
@@ -229,7 +222,7 @@ def _dispatch_call_args(cls=None, bound_call=None, unbound_call=None,
         kw_only = ()
         kw_only_defaults = {}
 
-    signature = _signature_from_spec(call)
+    signature = _get_signature(call)
 
     pos_args = spec.args
     if unbound_call is not None:

odl/space/fspace.py

@@ -14,10 +14,10 @@
 standard_library.install_aliases()
 from builtins import super
 
-from inspect import isfunction
+import inspect
 import numpy as np
+import sys
 
-from odl.operator.operator import Operator, _dispatch_call_args
 from odl.set import RealNumbers, ComplexNumbers, Set, LinearSpace
 from odl.set.space import LinearSpaceElement
 from odl.util import (
@@ -31,6 +31,57 @@
 __all__ = ('FunctionSpace',)
 
 
+def _check_out_arg(func):
+    """Check if of ``func`` has an (optional) ``out`` argument.
+
+    Also verify that the signature of ``func`` has no ``*args`` since
+    they make argument propagation a hassle.
+
+    Parameters
+    ----------
+    func : callable
+        Object that should be inspected.
+
+    Returns
+    -------
+    has_out : bool
+        ``True`` if the signature has an ``out`` argument, ``False``
+        otherwise.
+    out_is_optional : bool
+        ``True`` if ``out`` is present and optional in the signature,
+        ``False`` otherwise.
+
+    Raises
+    ------
+    TypeError
+        If ``func``'s signature has ``*args``.
+    """
+    if sys.version_info.major > 2:
+        spec = inspect.getfullargspec(func)
+        kw_only = spec.kwonlyargs
+    else:
+        spec = inspect.getargspec(func)
+        kw_only = ()
+
+    if spec.varargs is not None:
+        raise TypeError('*args not allowed in function signature')
+
+    pos_args = spec.args
+    pos_defaults = () if spec.defaults is None else spec.defaults
+
+    has_out = 'out' in pos_args or 'out' in kw_only
+    if 'out' in pos_args:
+        has_out = True
+        out_is_optional = (
+            pos_args.index('out') >= len(pos_args) - len(pos_defaults))
+    elif 'out' in kw_only:
+        has_out = out_is_optional = True
+    else:
+        has_out = out_is_optional = False
+
+    return has_out, out_is_optional
+
+
 def _default_in_place(func, x, out, **kwargs):
     """Default in-place evaluation method."""
     out[:] = func(x, **kwargs)
@@ -681,7 +732,7 @@ def __str__(self):
         return repr(self)
 
 
-class FunctionSpaceElement(LinearSpaceElement, Operator):
+class FunctionSpaceElement(LinearSpaceElement):
 
     """Representation of a `FunctionSpace` element."""
 
@@ -697,14 +748,14 @@ def __init__(self, fspace, fcall):
             It must return a `FunctionSpace.range` element or a
             `numpy.ndarray` of such (vectorized call).
         """
-        LinearSpaceElement.__init__(self, fspace)
-        Operator.__init__(self, self.space.domain, self.space.range,
-                          linear=False)
+        super().__init__(fspace)
+        self.__domain = self.space.domain
+        self.__range = self.space.range
 
         # Determine which type of implementation fcall is
         if isinstance(fcall, FunctionSpaceElement):
-            call_has_out, call_out_optional, _ = _dispatch_call_args(
-                bound_call=fcall._call)
+            call_has_out = fcall._call_has_out
+            call_out_optional = fcall._call_out_optional
 
         # Numpy Ufuncs and similar objects (e.g. Numba DUfuncs)
         elif hasattr(fcall, 'nin') and hasattr(fcall, 'nout'):
@@ -717,12 +768,10 @@ def __init__(self, fspace, fcall):
                                  'expected at most 1'
                                  ''.format(fcall.__name__, fcall.nout))
             call_has_out = call_out_optional = (fcall.nout == 1)
-        elif isfunction(fcall):
-            call_has_out, call_out_optional, _ = _dispatch_call_args(
-                unbound_call=fcall)
+        elif inspect.isfunction(fcall):
+            call_has_out, call_out_optional = _check_out_arg(fcall)
         elif callable(fcall):
-            call_has_out, call_out_optional, _ = _dispatch_call_args(
-                bound_call=fcall.__call__)
+            call_has_out, call_out_optional = _check_out_arg(fcall.__call__)
         else:
             raise TypeError('type {!r} not callable')
 
@@ -743,6 +792,16 @@ def __init__(self, fspace, fcall):
             self._call_out_of_place = preload_first_arg(self, 'out-of-place')(
                 _default_out_of_place)
 
+    @property
+    def domain(self):
+        """Set of objects on which this function can be evaluated."""
+        return self.__domain
+
+    @property
+    def range(self):
+        """Set in which the result of an evaluation of this function lies."""
+        return self.__range
+
     @property
     def out_dtype(self):
         """Output data type of this function.

odl/test/operator/operator_test.py

@@ -18,7 +18,7 @@
                  FunctionalLeftVectorMult, OperatorRightVectorMult,
                  MatrixOperator, OperatorLeftVectorMult,
                  OpTypeError, OpDomainError, OpRangeError)
-from odl.operator.operator import _signature_from_spec, _dispatch_call_args
+from odl.operator.operator import _get_signature, _dispatch_call_args
 from odl.util.testutils import almost_equal, all_almost_equal, noise_element
 
 
@@ -838,10 +838,10 @@ def func(request):
     return request.param
 
 
-def test_signature_from_spec(func):
+def test_get_signature(func):
 
     true_sig = func.__doc__.splitlines()[0].strip()
-    sig = _signature_from_spec(func)
+    sig = _get_signature(func)
     assert true_sig == sig
 
 

odl/test/space/fspace_test.py

@@ -316,6 +316,53 @@ def test_fspace_vector_eval_complex():
     assert all_equal(out_mg, true_mg)
 
 
+def test_fspace_vector_with_params():
+    rect, points, mg = _standard_setup_2d()
+
+    def f(x, c):
+        return sum(x) + c
+
+    def f_out1(x, out, c):
+        out[:] = sum(x) + c
+
+    def f_out2(x, c, out):
+        out[:] = sum(x) + c
+
+    fspace = FunctionSpace(rect)
+    true_result_arr = f(points, c=2)
+    true_result_mg = f(mg, c=2)
+
+    f_elem = fspace.element(f)
+    assert all_equal(f_elem(points, c=2), true_result_arr)
+    out_arr = np.empty((5,))
+    f_elem(points, c=2, out=out_arr)
+    assert all_equal(out_arr, true_result_arr)
+    assert all_equal(f_elem(mg, c=2), true_result_mg)
+    out_mg = np.empty((2, 3))
+    f_elem(mg, c=2, out=out_mg)
+    assert all_equal(out_mg, true_result_mg)
+
+    f_out1_elem = fspace.element(f_out1)
+    assert all_equal(f_out1_elem(points, c=2), true_result_arr)
+    out_arr = np.empty((5,))
+    f_out1_elem(points, c=2, out=out_arr)
+    assert all_equal(out_arr, true_result_arr)
+    assert all_equal(f_out1_elem(mg, c=2), true_result_mg)
+    out_mg = np.empty((2, 3))
+    f_out1_elem(mg, c=2, out=out_mg)
+    assert all_equal(out_mg, true_result_mg)
+
+    f_out2_elem = fspace.element(f_out2)
+    assert all_equal(f_out2_elem(points, c=2), true_result_arr)
+    out_arr = np.empty((5,))
+    f_out2_elem(points, c=2, out=out_arr)
+    assert all_equal(out_arr, true_result_arr)
+    assert all_equal(f_out2_elem(mg, c=2), true_result_mg)
+    out_mg = np.empty((2, 3))
+    f_out2_elem(mg, c=2, out=out_mg)
+    assert all_equal(out_mg, true_result_mg)
+
+
 def test_fspace_vector_ufunc():
     intv = odl.IntervalProd(0, 1)
     points = _points(intv, num=5)