Backport #10638 (#10643)

* Use less memory when loading EDF file (#10638) * Use less memory when loading EDF file * Add changelog entry * Formatting Co-authored-by: Alexandre Gramfort <alexandre.gramfort@m4x.org> * Restart CI Co-authored-by: Alexandre Gramfort <alexandre.gramfort@m4x.org> * Add changelog entry * Fix version * Change version to "unreleased" Co-authored-by: Alexandre Gramfort <alexandre.gramfort@m4x.org>
mne-tools · May 17, 2022 · 6a8dd14 · 6a8dd14
1 parent 5be1af6
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diff --git a/doc/changes/1.0.inc b/doc/changes/1.0.inc
@@ -16,6 +16,12 @@
 
    Also add a corresponding entry for yourself in doc/changes/names.inc
 
+.. _changes_1_0_4:
+
+Version 1.0.4 (unreleased)
+--------------------------
+- Reduce memory usage when loading an EDF file with ``preload=False`` (:gh:`10638` by `Clemens Brunner`_)
+
 .. _changes_1_0_3:
 
 Version 1.0.3 (2022-05-12)

diff --git a/mne/io/edf/edf.py b/mne/io/edf/edf.py
@@ -300,7 +300,8 @@ def _read_segment_file(data, idx, fi, start, stop, raw_extras, filenames,
             one = np.zeros((len(orig_sel), d_eidx - d_sidx), dtype=data.dtype)
             for ii, ci in enumerate(read_sel):
                 # This now has size (n_chunks_read, n_samp[ci])
-                ch_data = many_chunk[:, ch_offsets[ci]:ch_offsets[ci + 1]]
+                ch_data = many_chunk[:,
+                                     ch_offsets[ci]:ch_offsets[ci + 1]].copy()
 
                 if ci in tal_idx:
                     tal_data.append(ch_data)