fix #66/docs: add Windows & Blackwell troubleshooting

README.md

@@ -146,6 +146,34 @@ Inference note:
   - Some environments crash during `torch.compile`.
   - Disable compile: `TORCH_COMPILE=0 bash code/scripts/local_run.sh`.
   - Or try a safer mode: `TORCH_COMPILE=1 TORCH_COMPILE_MODE=reduce-overhead bash code/scripts/local_run.sh`.
+- **Blackwell GPUs (RTX 5080/5090, GB200/GB300)**:
+  - Stable PyTorch wheels (`cu124`) do not ship SM 12.0 kernels.
+    Install the nightly build with the `cu128` index:
+    ```bash
+    pip install --pre torch --index-url https://download.pytorch.org/whl/nightly/cu128
+    ```
+- **Windows (Git Bash / WSL)**:
+  - Triton is not supported on native Windows, which causes `torch.compile` to
+    fail. Disable it before running:
+    ```bash
+    export TORCH_COMPILE_DISABLE=1   # PyTorch-level flag
+    # or, equivalently for the repo scripts:
+    export PREDECODER_TORCH_COMPILE=0
+    ```
+  - When running scripts directly (outside the notebook or `local_run.sh`),
+    set the Python path so that repo modules are importable:
+    ```bash
+    export PYTHONPATH="code"
+    ```
+- **Pre-trained model not found during inference**:
+  - `find_best_model` searches inside `{output}/models/best_model/` first,
+    then falls back to `{output}/models/`. If you placed the downloaded
+    `.pt` file elsewhere, either move it into one of those directories or
+    point to it directly:
+    ```bash
+    PREDECODER_MODEL_CHECKPOINT_FILE=path/to/Ising-Decoder-SurfaceCode-1-Accurate.pt \
+      WORKFLOW=inference bash code/scripts/local_run.sh
+    ```
 
 ## Inference (pre-trained models)
 

code/workflows/run.py

@@ -140,7 +140,13 @@ def find_best_model(path, *, rank: int = 0):
             print(f"  [{marker}] {filename} (epoch {epoch_str})")
 
     if best_file is None:
-        raise FileNotFoundError(f"No valid model checkpoint files found in {path}")
+        raise FileNotFoundError(
+            f"No valid model checkpoint files found in {path}\n"
+            f"Expected .pt files (e.g. Ising-Decoder-SurfaceCode-1-Fast.pt or "
+            f"PreDecoderModelMemory_*.pt).\n"
+            f"Hint: download the pretrained weights and place them in this directory, "
+            f"or set model_checkpoint_file in your config to an explicit path."
+        )
 
     best_model_path = os.path.join(path, best_file)
     if rank == 0: