Update app.py

app.py

@@ -79,13 +79,115 @@ tokenizer = AutoTokenizer.from_pretrained(MODEL_ID)
 pipe = pipeline("text-generation", model=MODEL_ID, tokenizer=tokenizer)
 
 def llm_explain(record: dict) -> str:
-    if not record.get("ok", False):
-        return "Errors: " + "; ".join(record.get("errors", []))
-    comp = record["computed"]
-    inter = record["intermediate"]
-    Re_avg = (inter["Re1"] + inter["Re2"]) / 2
-    regime = "laminar" if Re_avg < 2300 else "turbulent"
-    return f"Pump head {comp['pump_head']:.3f} m, f={inter['friction_factor']:.4f}, h_f={inter['head_loss']:.3f} m. Flow regime: {regime}."
+    """
+    Grounded interpretation of the numeric results in `record`.
+    - No added facts beyond the numeric values present in `record`.
+    - No long tangents — only short, actionable interpretation.
+    """
+    if not isinstance(record, dict):
+        return "No numeric record provided."
+
+    if not record.get("ok", True):
+        return "Errors: " + "; ".join(record.get("errors", ["unknown error"]))
+
+    inter = record.get("intermediate", {}) or {}
+    comp = record.get("computed", {}) or {}
+
+    # helper: search for first available key in a dict
+    def find_first(d, keys):
+        for k in keys:
+            if k in d and d[k] is not None:
+                return d[k]
+        return None
+
+    # Pump head: try several likely keys
+    pump_head = find_first(comp, ["pump_head_required_m", "pump_head", "pump_head_m", "pump_head_required"])
+    # Head loss (Darcy-Weisbach)
+    h_f = find_first(inter, ["head_loss_hf_m", "head_loss", "head_loss_m", "head_loss_hf"])
+    # friction factor
+    f = find_first(inter, ["friction_factor_f", "friction_factor", "f"])
+    # Reynolds numbers
+    Re1 = find_first(inter, ["Re1", "re1"])
+    Re2 = find_first(inter, ["Re2", "re2"])
+
+    # convert to floats where possible
+    def as_float(x):
+        try:
+            return float(x)
+        except Exception:
+            return None
+
+    pump_head = as_float(pump_head)
+    h_f = as_float(h_f)
+    f = as_float(f)
+    Re1 = as_float(Re1)
+    Re2 = as_float(Re2)
+
+    # compute average Re and regime if possible
+    Re_avg = None
+    if (Re1 is not None) and (Re2 is not None):
+        Re_avg = (Re1 + Re2) / 2.0
+
+    if Re_avg is not None:
+        regime = "laminar" if Re_avg < 2300 else "turbulent"
+    else:
+        regime = "unknown"
+
+    parts = []
+
+    # 1) Short numeric summary (always the first sentence if any data exists)
+    summary_items = []
+    if pump_head is not None:
+        summary_items.append(f"pump head = {pump_head:.3f} m")
+    if h_f is not None:
+        summary_items.append(f"head loss = {h_f:.3f} m")
+    if f is not None:
+        summary_items.append(f"friction factor f = {f:.4f}")
+    if (Re1 is not None) and (Re2 is not None):
+        summary_items.append(f"Re1 = {int(Re1)}, Re2 = {int(Re2)} ({regime})")
+
+    if summary_items:
+        parts.append(". ".join(summary_items) + ".")
+
+    # 2) Direct interpretation comparing pump head and head loss
+    if (pump_head is not None) and (h_f is not None):
+        # tolerance: treat values within 1e-2 m or 1% as "approximately equal"
+        tol = max(1e-2, 0.01 * max(abs(pump_head), abs(h_f), 1.0))
+        diff = pump_head - h_f
+        if abs(diff) <= tol:
+            parts.append(
+                "Interpretation: pump head and frictional head loss are approximately equal, "
+                "so the system is near equilibrium (no net head gain)."
+            )
+        elif diff > 0:
+            parts.append(
+                f"Interpretation: pump head exceeds head loss by {diff:.3f} m — the pump can overcome frictional losses and provide net head to the system."
+            )
+        else:
+            parts.append(
+                f"Interpretation: pump head is lower than head loss by {abs(diff):.3f} m — the pump cannot fully overcome the frictional losses under these conditions."
+            )
+    else:
+        parts.append("Interpretation: insufficient data to directly compare pump head and head loss.")
+
+    # 3) Flow regime and friction factor context (concise and factual)
+    if regime != "unknown":
+        parts.append(f"Flow regime: {regime}.")
+    if f is not None:
+        parts.append("Friction factor was estimated (value shown above).")
+
+    # 4) Short, practical note (no speculation)
+    parts.append(
+        "Notes: the friction factor in this calculation is estimated numerically (Haaland approximation for turbulent flow); "
+        "these results are for preliminary assessment and assume steady, incompressible flow."
+    )
+
+    # Final safe fallback
+    explanation = " ".join(parts).strip()
+    if not explanation:
+        explanation = "No explanation could be generated from the provided record."
+    return explanation
+
 
 def compute_and_explain(P1,P2,V1,V2,z1,z2,rho,mu,D,L,roughness,use_darcy,mode):
     record = bernoulli_pipe_flow(P1,P2,V1,V2,z1,z2,rho,mu,roughness,D,L,None,use_darcy)