Improve training agent progress reporting

tools/train_torch_recurrent_forecaster.py

@@ -118,6 +118,10 @@ def main() -> None:
     target_horizons = _horizons(args.horizons, decision_horizon)
     feature_names = _feature_names_arg(args.features)
     round_trip_cost = max(0.0, 2.0 * (float(settings.taker_fee_rate) + float(settings.slippage_rate)))
+    _progress(
+        f"training started: symbols={len(symbols)} interval={interval} "
+        f"limit={args.limit} epochs={args.epochs}"
+    )
 
     artifact: dict[str, Any] = {
         "version": 4,
@@ -141,7 +145,9 @@ def main() -> None:
         "symbols": {},
     }
 
-    for symbol in symbols:
+    total_symbols = len(symbols)
+    for index, symbol in enumerate(symbols, start=1):
+        _progress(f"{symbol}: training started ({index}/{total_symbols})")
         result = _train_symbol(
             client=client,
             symbol=symbol,
@@ -170,10 +176,10 @@ def main() -> None:
             seed=args.seed,
         )
         if result is None:
-            print(f"{symbol}: skipped, not enough candles or train/validation samples")
+            _progress(f"{symbol}: skipped, not enough candles or train/validation samples")
             continue
         artifact["symbols"][symbol] = result
-        print(
+        _progress(
             f"{symbol}: model={result['model']} lookback={result['lookback']} "
             f"features={result['input_size']} hidden={result['hidden_size']} "
             f"layers={result['num_layers']} horizons={','.join(map(str, result['target_horizons']))} "
@@ -187,7 +193,11 @@ def main() -> None:
     tmp_output = output.with_name(f"{output.name}.tmp")
     tmp_output.write_text(json.dumps(artifact, ensure_ascii=False, indent=2) + "\n", encoding="utf-8")
     tmp_output.replace(output)
-    print(f"saved {output}")
+    _progress(f"saved {output}")
+
+
+def _progress(message: str) -> None:
+    print(message, flush=True)
 
 
 def _parse_args() -> argparse.Namespace:
@@ -274,12 +284,13 @@ def _train_symbol(
             add_indicators(rows)
             market_candles[context_symbol] = rows
         except Exception as exc:
-            print(f"{symbol}: context {context_symbol} skipped: {exc}")
+            _progress(f"{symbol}: context {context_symbol} skipped: {exc}")
     trend_candles = _historical_klines(client, symbol, "D", min(max(260, limit // 24 + 260), 1000))
     add_indicators(trend_candles)
 
     best: dict[str, Any] | None = None
     for lookback in lookbacks:
+        _progress(f"{symbol}: preparing lookback={lookback}")
         prepared = _prepare_data(
             candles=candles,
             feature_names=feature_names,
@@ -307,6 +318,11 @@ def _train_symbol(
                     for dropout in dropouts:
                         if num_layers <= 1 and dropout != 0.0:
                             continue
+                        _progress(
+                            f"{symbol}: fitting {architecture} "
+                            f"lookback={lookback} hidden={hidden_size} "
+                            f"layers={num_layers} dropout={dropout}"
+                        )
                         candidate = _fit_candidate(
                             prepared=prepared,
                             architecture=architecture,