From f02e5c9c31a66c16fbd4977544906304d2af1707 Mon Sep 17 00:00:00 2001
From: Laura Sandoval <laurasandoval@Lauras-MacBook-Pro.local>
Date: Tue, 3 Feb 2026 14:07:00 -0700
Subject: [PATCH] select last from time

---
 imap_processing/ialirt/l0/process_swe.py | 28 ++++++++++--------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/imap_processing/ialirt/l0/process_swe.py b/imap_processing/ialirt/l0/process_swe.py
index 7389f28f7..a72c8f0b5 100644
--- a/imap_processing/ialirt/l0/process_swe.py
+++ b/imap_processing/ialirt/l0/process_swe.py
@@ -520,6 +520,11 @@ def process_swe(accumulated_data: xr.Dataset, in_flight_cal_files: list) -> list
 
         # Interpolate to find the correct calibration factor
         in_flight_cal_df = read_in_flight_cal_data(in_flight_cal_files)
+        in_flight_cal_df = (
+            in_flight_cal_df.dropna(subset=["met_time"])
+            .sort_values("met_time")
+            .reset_index(drop=True)
+        )
         # Get names of all 7 cems in the calibration file
         cal_cols = [f"cem{i}" for i in range(1, 8)]
         cal_met = in_flight_cal_df["met_time"].to_numpy()
@@ -533,15 +538,10 @@ def process_swe(accumulated_data: xr.Dataset, in_flight_cal_files: list) -> list
         ) // 2
 
         # Interpolate to the appropriate calibration factor
+        idx = np.searchsorted(cal_met, group_time_first_half_mid, side="right") - 1
+
         interp_cal_first_half = np.array(
-            [
-                np.interp(
-                    int(group_time_first_half_mid),
-                    cal_met,
-                    in_flight_cal_df[cem].to_numpy(),
-                )
-                for cem in cal_cols
-            ],
+            [in_flight_cal_df[cem].iloc[idx] for cem in cal_cols],
             dtype=np.float64,
         )
         # Find the middle timestamp of the second group
@@ -551,16 +551,10 @@ def process_swe(accumulated_data: xr.Dataset, in_flight_cal_files: list) -> list
         group_time_second_half_mid = (
             group_time_second_half[0] + group_time_second_half[-1]
         ) // 2
-        # Interpolate to the appropriate calibration factor
+        idx = np.searchsorted(cal_met, group_time_second_half_mid, side="right") - 1
+
         interp_cal_second_half = np.array(
-            [
-                np.interp(
-                    int(group_time_second_half_mid),
-                    cal_met,
-                    in_flight_cal_df[cem].to_numpy(),
-                )
-                for cem in cal_cols
-            ],
+            [in_flight_cal_df[cem].iloc[idx] for cem in cal_cols],
             dtype=np.float64,
         )