Include the right edge of the search window in correct_peaks

shift_peaks sliced sig[ind - r : min(ind + r, sig_len - 1)], which
leaves out ind + r and the last sample of the signal. A peak exactly
search_radius samples after the original index, or on the last sample,
could not be found.

Author: TheNetherWatcher

docs/changes.rst

@@ -35,6 +35,9 @@ Unreleased
 **Use Ruff for formatting and linting**
   The ``dev`` extra now includes ``ruff`` instead of ``black`` and ``pylint``, and the code is formatted with a line length of 88 (the default).
 
+**Fix search window in correct_peaks**
+  ``correct_peaks`` now searches ``search_radius`` samples on both sides of each peak, including the last sample of the signal. It used to stop one sample short on the right, so a peak exactly ``search_radius`` samples after the original index, or on the last sample, could not be found.
+
 Version 4.3.1 (Feb 2026)
 -----------------------------
 

src/wfdb/processing/peaks.py

@@ -225,7 +225,7 @@ def shift_peaks(sig, peak_inds, search_radius, peak_up):
     for i in range(n_peaks):
         ind = peak_inds[i]
         local_sig = sig[
-            max(0, ind - search_radius) : min(ind + search_radius, sig_len - 1)
+            max(0, ind - search_radius) : min(ind + search_radius + 1, sig_len)
         ]
 
         if peak_up:

tests/test_processing.py

@@ -173,6 +173,21 @@ def test_correct_peaks(self):
 
         assert np.array_equal(yz, expected_peaks)
 
+    def test_correct_peaks_window_edges(self):
+        """Peaks at the edge of the search radius or the signal are found."""
+        sig = np.zeros(30)
+        sig[13] = 5
+        sig[29] = 5
+
+        # Peak exactly search_radius samples after the guess
+        assert processing.correct_peaks(
+            sig, np.array([10]), search_radius=3, smooth_window_size=9, peak_dir="up"
+        ).tolist() == [13]
+        # Peak on the last sample of the signal
+        assert processing.correct_peaks(
+            sig, np.array([27]), search_radius=5, smooth_window_size=9, peak_dir="up"
+        ).tolist() == [29]
+
 
 class TestComputeHr:
     """Tests for compute_hr."""