add missing file

nifty5/operators/hartley_operator.py

+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# Copyright(C) 2013-2018 Max-Planck-Society
+#
+# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik
+# and financially supported by the Studienstiftung des deutschen Volkes.
+
+from __future__ import absolute_import, division, print_function
+
+import numpy as np
+
+from .. import dobj, utilities
+from ..compat import *
+from ..domain_tuple import DomainTuple
+from ..domains.rg_space import RGSpace
+from ..field import Field
+from .linear_operator import LinearOperator
+
+
+class HartleyOperator(LinearOperator):
+    """Transforms between a pair of position and harmonic RGSpaces.
+
+    Parameters
+    ----------
+    domain: Domain, tuple of Domain or DomainTuple
+        The domain of the data that is input by "times" and output by
+        "adjoint_times".
+    target: Domain, optional
+        The target (sub-)domain of the transform operation.
+        If omitted, a domain will be chosen automatically.
+    space: int, optional
+        The index of the subdomain on which the operator should act
+        If None, it is set to 0 if `domain` contains exactly one space.
+        `domain[space]` must be an RGSpace.
+    """
+
+    def __init__(self, domain, target=None, space=None):
+        super(HartleyOperator, self).__init__()
+
+        # Initialize domain and target
+        self._domain = DomainTuple.make(domain)
+        self._space = utilities.infer_space(self._domain, space)
+
+        adom = self._domain[self._space]
+        if not isinstance(adom, RGSpace):
+            raise TypeError("HartleyOperator only works on RGSpaces")
+        if target is None:
+            target = adom.get_default_codomain()
+
+        self._target = [dom for dom in self._domain]
+        self._target[self._space] = target
+        self._target = DomainTuple.make(self._target)
+        adom.check_codomain(target)
+        target.check_codomain(adom)
+
+        utilities.fft_prep()
+
+    def apply(self, x, mode):
+        self._check_input(x, mode)
+        if np.issubdtype(x.dtype, np.complexfloating):
+            return (self._apply_cartesian(x.real, mode) +
+                    1j*self._apply_cartesian(x.imag, mode))
+        else:
+            return self._apply_cartesian(x, mode)
+
+    def _apply_cartesian(self, x, mode):
+        axes = x.domain.axes[self._space]
+        tdom = self._tgt(mode)
+        oldax = dobj.distaxis(x.val)
+        if oldax not in axes:  # straightforward, no redistribution needed
+            ldat = x.local_data
+            ldat = utilities.hartley(ldat, axes=axes)
+            tmp = dobj.from_local_data(x.val.shape, ldat, distaxis=oldax)
+        elif len(axes) < len(x.shape) or len(axes) == 1:
+            # we can use one Hartley pass in between the redistributions
+            tmp = dobj.redistribute(x.val, nodist=axes)
+            newax = dobj.distaxis(tmp)
+            ldat = dobj.local_data(tmp)
+            ldat = utilities.hartley(ldat, axes=axes)
+            tmp = dobj.from_local_data(tmp.shape, ldat, distaxis=newax)
+            tmp = dobj.redistribute(tmp, dist=oldax)
+        else:  # two separate, full FFTs needed
+            # ideal strategy for the moment would be:
+            # - do real-to-complex FFT on all local axes
+            # - fill up array
+            # - redistribute array
+            # - do complex-to-complex FFT on remaining axis
+            # - add re+im
+            # - redistribute back
+            rem_axes = tuple(i for i in axes if i != oldax)
+            tmp = x.val
+            ldat = dobj.local_data(tmp)
+            ldat = utilities.my_fftn_r2c(ldat, axes=rem_axes)
+            if oldax != 0:
+                raise ValueError("bad distribution")
+            ldat2 = ldat.reshape((ldat.shape[0],
+                                  np.prod(ldat.shape[1:])))
+            shp2d = (x.val.shape[0], np.prod(x.val.shape[1:]))
+            tmp = dobj.from_local_data(shp2d, ldat2, distaxis=0)
+            tmp = dobj.transpose(tmp)
+            ldat2 = dobj.local_data(tmp)
+            ldat2 = utilities.my_fftn(ldat2, axes=(1,))
+            ldat2 = ldat2.real+ldat2.imag
+            tmp = dobj.from_local_data(tmp.shape, ldat2, distaxis=0)
+            tmp = dobj.transpose(tmp)
+            ldat2 = dobj.local_data(tmp).reshape(ldat.shape)
+            tmp = dobj.from_local_data(x.val.shape, ldat2, distaxis=0)
+        Tval = Field(tdom, tmp)
+        if mode & (LinearOperator.TIMES | LinearOperator.ADJOINT_TIMES):
+            fct = self._domain[self._space].scalar_dvol
+        else:
+            fct = self._target[self._space].scalar_dvol
+        return Tval if fct == 1 else Tval*fct
+
+    @property
+    def domain(self):
+        return self._domain
+
+    @property
+    def target(self):
+        return self._target
+
+    @property
+    def capability(self):
+        return self._all_ops