Make the Python Wrapper more Hackable and simplify Quantization (#1010)

* Some first `Module` implementations

* Add `state_dict` and `load_state_dict` functionality

* Move modules around and create `candle.nn.Linear`

* Add `nn.Embedding` and `nn.LayerNorm`

* Add BERT implementation

* Batch q-matmul

* Automatically dequantize `QTensors` if a `Tensor` is expected

* Add Module `.to()`, `.cuda()`, `cpu()` and `.type()` functionality

* Unittests for `Module`, `Tensor` and `candle.utils`

* Add `pytorch` like slicing to `Tensor`

* Cleanup and BERT fixes

* `black` formatting + unit-test for `nn.Linear`

* Refactor slicing implementation

candle-pyo3/py_src/candle/__init__.py

@@ -1,5 +1,30 @@
-from .candle import *
+import logging
+
+try:
+    from .candle import *
+except ImportError as e:
+    # If we are in development mode, or we did not bundle the CUDA DLLs, we try to locate them here
+    logging.warning("CUDA DLLs were not bundled with this package. Trying to locate them...")
+    import os
+    import platform
+
+    # Try to locate CUDA_PATH environment variable
+    cuda_path = os.environ.get("CUDA_PATH", None)
+    if cuda_path:
+        logging.warning(f"Found CUDA_PATH environment variable: {cuda_path}")
+        if platform.system() == "Windows":
+            cuda_path = os.path.join(cuda_path, "bin")
+        else:
+            cuda_path = os.path.join(cuda_path, "lib64")
+
+        logging.warning(f"Adding {cuda_path} to DLL search path...")
+        os.add_dll_directory(cuda_path)
+
+    try:
+        from .candle import *
+    except ImportError as inner_e:
+        raise ImportError("Could not locate CUDA DLLs. Please check the documentation for more information.")
 
 __doc__ = candle.__doc__
 if hasattr(candle, "__all__"):
-    __all__ = candle.__all__
+    __all__ = candle.__all__