Proposed file structure rework and required file changes

bitsandbytes_windows/cextension.py

@@ -0,0 +1,54 @@
+import ctypes as ct
+from pathlib import Path
+from warnings import warn
+
+from .cuda_setup.main import evaluate_cuda_setup
+
+
+class CUDALibrary_Singleton(object):
+    _instance = None
+
+    def __init__(self):
+        raise RuntimeError("Call get_instance() instead")
+
+    def initialize(self):
+        binary_name = evaluate_cuda_setup()
+        package_dir = Path(__file__).parent
+        binary_path = package_dir / binary_name
+
+        if not binary_path.exists():
+            print(f"CUDA SETUP: TODO: compile library for specific version: {binary_name}")
+            legacy_binary_name = "libbitsandbytes.so"
+            print(f"CUDA SETUP: Defaulting to {legacy_binary_name}...")
+            binary_path = package_dir / legacy_binary_name
+            if not binary_path.exists():
+                print('CUDA SETUP: CUDA detection failed. Either CUDA driver not installed, CUDA not installed, or you have multiple conflicting CUDA libraries!')
+                print('CUDA SETUP: If you compiled from source, try again with `make CUDA_VERSION=DETECTED_CUDA_VERSION` for example, `make CUDA_VERSION=113`.')
+                raise Exception('CUDA SETUP: Setup Failed!')
+            # self.lib = ct.cdll.LoadLibrary(binary_path)
+            self.lib = ct.cdll.LoadLibrary(str(binary_path))            # $$$
+        else:
+            print(f"CUDA SETUP: Loading binary {binary_path}...")
+            # self.lib = ct.cdll.LoadLibrary(binary_path)
+            self.lib = ct.cdll.LoadLibrary(str(binary_path))            # $$$
+
+    @classmethod
+    def get_instance(cls):
+        if cls._instance is None:
+            cls._instance = cls.__new__(cls)
+            cls._instance.initialize()
+        return cls._instance
+
+
+lib = CUDALibrary_Singleton.get_instance().lib
+try:
+    lib.cadam32bit_g32
+    lib.get_context.restype = ct.c_void_p
+    lib.get_cusparse.restype = ct.c_void_p
+    COMPILED_WITH_CUDA = True
+except AttributeError:
+    warn(
+        "The installed version of bitsandbytes was compiled without GPU support. "
+        "8-bit optimizers and GPU quantization are unavailable."
+    )
+    COMPILED_WITH_CUDA = False