fix: linear-interpolation

Author: binary69

diff_output.txt

@@ -315,8 +315,8 @@ def interpolate(
             idx_upper = idx_upper[~overflow_mask]
             idx_lower = idx_lower[~overflow_mask]
 
-            times_lower = idx_lower * self.time_delta
-            times_upper = idx_upper * self.time_delta
+            times_lower = self.start_time +  (idx_lower * self.time_delta)
+            times_upper = self.start_time + (idx_upper * self.time_delta)
             denom = times_upper - times_lower
 
             times_valid = valid_times[~overflow_mask]
@@ -449,14 +449,12 @@ def interpolate(
 
             valid = valid[~overflow_mask.any(axis=1)]
 
-            times_lower = idx_lower * self.time_delta
-            times_upper = idx_upper * self.time_delta
+            times_lower = self.start_time + (idx_lower * self.time_delta) + self._phase_shifts[np.newaxis, :]
+            times_upper = self.start_time + (idx_upper * self.time_delta) + self._phase_shifts[np.newaxis, :]   
             denom = times_upper - times_lower
 
-            time_dim = valid_times[:, np.newaxis] - self._phase_shifts[np.newaxis, :]
-
-            lower_numerator = times_upper - time_dim
-            upper_numerator = time_dim - times_lower
+            lower_numerator = times_upper - valid_times[:, np.newaxis]
+            upper_numerator = valid_times[:, np.newaxis] - times_lower
 
             lower_signal_ratio = lower_numerator / denom
             upper_signal_ratio = upper_numerator / denom

experanto/interpolators.py

@@ -216,14 +216,16 @@ def test_nearest_neighbor_interpolation_with_phase_shifts_handles_nans(
 @pytest.mark.parametrize("use_mem_mapped", [False, True])
 @pytest.mark.parametrize("contain_nans", [False, True])
 @pytest.mark.parametrize("keep_nans", [False, True])
+@pytest.mark.parametrize("start_time", [0.0, 15.0])
 def test_linear_interpolation(
-    n_signals, sampling_rate, use_mem_mapped, contain_nans, keep_nans
+    n_signals, sampling_rate, use_mem_mapped, contain_nans, keep_nans, start_time
 ):
     with sequence_data_and_interpolator(
         data_kwargs={
             "n_signals": n_signals,
             "use_mem_mapped": use_mem_mapped,
-            "t_end": 5.0,
+            "start_time": start_time,
+            "t_end": start_time + 5.0,
             "sampling_rate": sampling_rate,
             "contain_nans": contain_nans,
         },
@@ -269,14 +271,16 @@ def test_linear_interpolation(
 @pytest.mark.parametrize("sampling_rate", [3.0, 10.0, 100.0])
 @pytest.mark.parametrize("use_mem_mapped", [False, True])
 @pytest.mark.parametrize("keep_nans", [False, True])
+@pytest.mark.parametrize("start_time", [0.0, 15.0])
 def test_linear_interpolation_with_phase_shifts(
-    n_signals, sampling_rate, use_mem_mapped, keep_nans
+    n_signals, sampling_rate, use_mem_mapped, keep_nans, start_time
 ):
     with sequence_data_and_interpolator(
         data_kwargs={
             "n_signals": n_signals,
             "use_mem_mapped": use_mem_mapped,
-            "t_end": 5.0,
+            "start_time": start_time,
+            "t_end": start_time + 5.0,
             "sampling_rate": sampling_rate,
             "shifts_per_signal": True,
         },