fix: yaml 1.1 parses '2250.0e12' as string -> float() cast in MFU calc (crashed first log step)

tinyvla_b200/scripts/train_fast.py

@@ -319,8 +319,9 @@ def main():
             torch.cuda.synchronize()
             el = time.time() - t0
             sps = seen * world / el  # глобально по всем рангам
-            gflops = cfg.get("gflops_per_sample", 360.0)
-            mfu = sps * gflops * 1e9 / (cfg.get("peak_flops", 989e12)) * 100
+            # float(): yaml 1.1 парсит "2250.0e12" без знака экспоненты как строку
+            gflops = float(cfg.get("gflops_per_sample", 360.0))
+            mfu = sps * gflops * 1e9 / float(cfg.get("peak_flops", 989e12)) * 100
             eta = (steps - step) * eff_batch / sps / 3600
             log(f"step {step}/{steps} loss {info['loss']:.4f} | {sps:.0f} samples/s "
                   f"| {step/el:.2f} it/s | MFU~{mfu:.0f}% | eta {eta:.2f} h "