Removed _extend_using_coroutines

Author: MarcCote

nibabel/streamlines/array_sequence.py

@@ -240,67 +240,6 @@ def extend(self, elements):
 
         self.finalize_append()
 
-    def _extend_using_coroutine(self, buffer_size=4):
-        """ Creates a coroutine allowing to append elements.
-
-        Parameters
-        ----------
-        buffer_size : float, optional
-            Size (in Mb) for memory pre-allocation.
-
-        Returns
-        -------
-        coroutine
-            Coroutine object which expects the values to be appended to this
-            array sequence.
-
-        Notes
-        -----
-        This method is essential for
-        :func:`create_arraysequences_from_generator` as it allows for an
-        efficient way of creating multiple array sequences in a hyperthreaded
-        fashion and still benefit from the memory buffering. Whitout this
-        method the alternative would be to use :meth:`append` which does
-        not have such buffering mechanism and thus is at least one order of
-        magnitude slower.
-        """
-        offsets = []
-        lengths = []
-
-        offset = self._get_next_offset()
-        try:
-            first_element = True
-            while True:
-                e = (yield)
-                e = np.asarray(e)
-                if first_element:
-                    first_element = False
-                    n_rows_buffer = int(buffer_size * 1024**2 // e.nbytes)
-                    new_shape = (n_rows_buffer,) + e.shape[1:]
-                    if len(self) == 0:
-                        self._data = np.empty(new_shape, dtype=e.dtype)
-
-                end = offset + len(e)
-                if end > len(self._data):
-                    # Resize needed, adding `len(e)` items plus some buffer.
-                    nb_points = len(self._data)
-                    nb_points += len(e) + n_rows_buffer
-                    self._data.resize((nb_points,) + self.common_shape)
-
-                offsets.append(offset)
-                lengths.append(len(e))
-                self._data[offset:offset + len(e)] = e
-                offset += len(e)
-
-        except GeneratorExit:
-            pass
-
-        self._offsets = np.r_[self._offsets, offsets].astype(np.intp)
-        self._lengths = np.r_[self._lengths, lengths].astype(np.intp)
-
-        # Clear unused memory.
-        self._data.resize((offset,) + self.common_shape)
-
     def copy(self):
         """ Creates a copy of this :class:`ArraySequence` object.
 

nibabel/streamlines/tests/test_array_sequence.py

@@ -204,37 +204,6 @@ def test_arraysequence_extend(self):
         seq = SEQ_DATA['seq'].copy()  # Copy because of in-place modification.
         assert_raises(ValueError, seq.extend, data)
 
-    def test_arraysequence_extend_using_coroutine(self):
-        new_data = generate_data(nb_arrays=10,
-                                 common_shape=SEQ_DATA['seq'].common_shape,
-                                 rng=SEQ_DATA['rng'])
-
-        # Extend with an empty list.
-        seq = SEQ_DATA['seq'].copy()  # Copy because of in-place modification.
-        coroutine = seq._extend_using_coroutine()
-        coroutine.send(None)
-        coroutine.close()
-        check_arr_seq(seq, SEQ_DATA['data'])
-
-        # Extend with a list of ndarrays.
-        seq = SEQ_DATA['seq'].copy()  # Copy because of in-place modification.
-        coroutine = seq._extend_using_coroutine()
-        coroutine.send(None)
-        for e in new_data:
-            coroutine.send(e)
-        coroutine.close()
-        check_arr_seq(seq, SEQ_DATA['data'] + new_data)
-
-        # Extend with elements of different shape.
-        data = generate_data(nb_arrays=10,
-                             common_shape=SEQ_DATA['seq'].common_shape*2,
-                             rng=SEQ_DATA['rng'])
-        seq = SEQ_DATA['seq'].copy()  # Copy because of in-place modification.
-
-        coroutine = seq._extend_using_coroutine()
-        coroutine.send(None)
-        assert_raises(ValueError, coroutine.send, data[0])
-
     def test_arraysequence_getitem(self):
         # Get one item
         for i, e in enumerate(SEQ_DATA['seq']):