Update app.py

app.py

@@ -4,7 +4,7 @@
 # Guided scenarios (ACTIVE):
 #   A) Straight heading
 #   B) Variable heading & speed  (beam search, BTO-first)
-#   C) Variable heading & speed (SE bias after 22:40)  (beam search, BTO-first + tiny east bias only after 22:40)
+#   C) Variable heading & speed (SE after 22:40)  (beam search, BTO-first + HARD heading band 175–180 after 22:40)
 #
 # Key behavior:
 # - Last radar spot FIXED: 18:22:00Z @ 6.578N, 96.341E
@@ -22,9 +22,9 @@
 # PERFORMANCE:
 # - Straight heading mode keeps Top-K polish.
 # - Variable heading & speed uses beam search and skips polish by default (much faster).
-# - SE mode reuses the same beam search, but only AFTER 22:40 adds a tiny penalty
-#   for "westward" heading increases, nudging the solution slightly toward the east
-#   while keeping BTO as the primary objective.
+# - SE mode reuses the same beam search, but from 22:40 onward it HARD-CONSTRAINS
+#   the last two leg headings into 175–180° (more southeast), with an optional tiny
+#   penalty for heading increases within that band.
 
 import os
 import re
@@ -142,13 +142,18 @@ VAR_HEADING_DELTA_SET = [-6, -3, 0, 3, 6]  # candidate changes per segment (deg)
 VAR_BEAM_WIDTH = 12                  # keep top-N partial paths each segment
 VAR_SMOOTH_PENALTY_US_PER_DEG = 1.5  # small penalty to avoid wiggles (still BTO-first)
 
-# ===== SE-bias-after-22:40 (new mode) =====
+# ===== SE-after-22:40 (HARD CONSTRAINT mode) =====
 # Only applied to the last two segments (22:40→00:10, 00:10→00:20).
-# Penalty is applied ONLY when heading increases (more west-of-south),
-# nudging solutions to be slightly more east while keeping BTO primary.
-SE_EAST_DIVERGE_START_SEG_INDEX = 4          # segment indices: 0..5 ; seg 3 ends at 22:40, seg 4 starts after 22:40
-SE_VAR_EAST_DELTA_SET = [-8, -4, -2, 0, 2]   # prefer small decreases (eastward) after 22:40
-SE_EAST_BIAS_PENALTY_US_PER_DEG = 0.8        # small; BTO still dominates
+# We constrain headings into a SE band so the path *must* go more east after 22:40.
+SE_EAST_DIVERGE_START_SEG_INDEX = 4          # seg indices: 0..5 ; seg 4 starts after 22:40
+SE_POST2240_HDG_MIN = 175.0
+SE_POST2240_HDG_MAX = 180.0
+
+# Candidate deltas for post-22:40 segments: allow stronger "eastward" moves (lower heading)
+SE_VAR_EAST_DELTA_SET = [-16, -12, -8, -6, -4, -2, 0, 2]
+
+# Optional tiny penalty if heading increases after 22:40 (nudges toward the lower end of the band)
+SE_EAST_BIAS_PENALTY_US_PER_DEG = 0.8
 
 # Search area colors (optional)
 SEARCH_AREA_COLORS = {
@@ -1650,9 +1655,15 @@ def _solve_guided_variable_core(method, alt_ft, vs_fpm, descent_start_choice, se
 
                 # choose heading deltas:
                 # - normal: VAR_HEADING_DELTA_SET for all segments
-                # - SE mode: after 22:40 (segments 4 and 5), use SE_VAR_EAST_DELTA_SET
+                # - SE mode: after 22:40 (segments 4 and 5), HARD clamp heading into [175, 180]
                 use_se_bias = bool(se_bias_after_2240 and seg_i >= SE_EAST_DIVERGE_START_SEG_INDEX)
-                delta_set = SE_VAR_EAST_DELTA_SET if use_se_bias else VAR_HEADING_DELTA_SET
+
+                if use_se_bias:
+                    delta_set = SE_VAR_EAST_DELTA_SET
+                    lo_h, hi_h = float(SE_POST2240_HDG_MIN), float(SE_POST2240_HDG_MAX)
+                else:
+                    delta_set = VAR_HEADING_DELTA_SET
+                    lo_h, hi_h = float(VAR_HEADING_MIN), float(VAR_HEADING_MAX)
 
                 for st in beam:
                     h_prev = float(st["h_prev"])
@@ -1660,8 +1671,14 @@ def _solve_guided_variable_core(method, alt_ft, vs_fpm, descent_start_choice, se
                     cand_h = []
                     for d in delta_set:
                         h_try = h_prev + float(d)
-                        h_try = _clamp(h_try, VAR_HEADING_MIN, VAR_HEADING_MAX)
+                        h_try = _clamp(h_try, lo_h, hi_h)
                         cand_h.append(h_try)
+
+                    # ensure band edges are always possible candidates in SE mode
+                    if use_se_bias:
+                        cand_h.append(lo_h)
+                        cand_h.append(hi_h)
+
                     cand_h = sorted(list({round(x, 6): x for x in cand_h}.values()))
 
                     for h_try in cand_h:
@@ -1684,7 +1701,7 @@ def _solve_guided_variable_core(method, alt_ft, vs_fpm, descent_start_choice, se
                         abs_err = 0.0 if meas is None or (err_seg != err_seg) else abs(float(err_seg))
                         smooth_pen = abs(float(h_try) - float(h_prev)) * VAR_SMOOTH_PENALTY_US_PER_DEG
 
-                        # SE bias only AFTER 22:40: penalize heading increases (more west-of-south)
+                        # Optional tiny penalty in SE band: penalize heading increases (less SE)
                         east_bias_pen = 0.0
                         if use_se_bias:
                             dh = float(h_try) - float(h_prev)
@@ -1782,13 +1799,14 @@ def _solve_guided_variable_core(method, alt_ft, vs_fpm, descent_start_choice, se
         ]
     else:
         report_lines = [
-            "**Guided mode: Variable heading & speed (SE bias after 22:40) + computed turn (18:22→18:40), clipped to 00:20**",
-            "- Solver mode: **BTO-first ring-fit (beam search) + tiny east bias after 22:40**",
+            "**Guided mode: Variable heading & speed (SE after 22:40) + computed turn (18:22→18:40), clipped to 00:20**",
+            "- Solver mode: **BTO-first ring-fit (beam search) + HARD SE heading band after 22:40**",
             f"- Turn speed: **{best_global_info['v_turn']:.2f} kt** (range {TURN_SPEED_MIN_KT:.0f}–{TURN_SPEED_MAX_KT:.0f})",
             f"- Beam width: **{VAR_BEAM_WIDTH}**",
             f"- Normal heading deltas (pre-22:40): **{VAR_HEADING_DELTA_SET}°**",
-            f"- SE heading deltas (post-22:40): **{SE_VAR_EAST_DELTA_SET}°**",
-            f"- Smooth penalty: **{VAR_SMOOTH_PENALTY_US_PER_DEG:.2f} µs/deg** | East-bias penalty: **{SE_EAST_BIAS_PENALTY_US_PER_DEG:.2f} µs/deg** (only if heading increases after 22:40)",
+            f"- Post-22:40 heading band: **[{SE_POST2240_HDG_MIN:.1f}°, {SE_POST2240_HDG_MAX:.1f}°]**",
+            f"- Post-22:40 deltas (inside band): **{SE_VAR_EAST_DELTA_SET}°**",
+            f"- Smooth penalty: **{VAR_SMOOTH_PENALTY_US_PER_DEG:.2f} µs/deg** | Optional increase-penalty: **{SE_EAST_BIAS_PENALTY_US_PER_DEG:.2f} µs/deg**",
             "",
             "**Per-segment heading & speed:**",
             f"- 18:40→19:40: **{hs[0]:.2f}°**, **{vs[0]:.2f} kt** (end err {es[0]:+.2f} µs)",
@@ -1803,7 +1821,7 @@ def _solve_guided_variable_core(method, alt_ft, vs_fpm, descent_start_choice, se
             f"- RMSE_BTO at enforced times: **{best_global_info['rmse_bto_us']:.2f} µs**",
             "",
             "*If 18:40 has no measured BTO in your satLoc, it is automatically not enforced.*",
-            "*This mode preserves the same BTO-first behavior and only nudges the final two legs slightly east when it can do so without breaking the ring-fit.*",
+            "*SE mode guarantees 175–180° from 22:40 onwards (more southeast). If this makes BTO worse, widen the band slightly.*",
         ]
 
     return best_global_legs, "\n".join(report_lines), start_dt
@@ -1911,7 +1929,7 @@ with gr.Blocks() as demo:
         f"**Southern speed bounds:** {SOUTH_SPEED_MIN_KT:.0f}–{SOUTH_SPEED_MAX_KT:.0f} kt\n"
         f"**Straight mode:** Top-K polish (top-{TOPK_POLISH})\n"
         f"**Variable mode:** beam search (width {VAR_BEAM_WIDTH})\n"
-        f"**SE mode:** same beam search, but adds a tiny east bias only after 22:40"
+        f"**SE mode:** beam search + HARD heading band **{SE_POST2240_HDG_MIN:.0f}–{SE_POST2240_HDG_MAX:.0f}°** from 22:40 onwards"
     )
 
     guided_mode = gr.Dropdown(