Try to improve robustness of finding cuda in build. Try to support building with CUDA 8.

setup.py

@@ -17,10 +17,16 @@ import ctypes.util
 
 import torch
 
-#Takes a path to walk
-#A function to decide if to keep
-#collection if we want a list of all occurances
 def find(path, regex_func, collect=False):
+    """
+    Recursively searches through a directory with regex_func and
+    either collects all instances or returns the first instance.
+    
+    Args:
+        path: Directory to search through
+        regex_function: A function to run on each file to decide if it should be returned/collected
+        collect (False) : If True will collect all instances of matching, else will return first instance only 
+    """
     collection = [] if collect else None
     for root, dirs, files in os.walk(path):
         for file in files:
@@ -31,25 +37,55 @@ def find(path, regex_func, collect=False):
                     return os.path.join(root, file)
     return list(set(collection))
 
+
 def findcuda():
+    """
+    Based on PyTorch build process. Will look for nvcc for compilation.
+    Either will set cuda home by enviornment variable CUDA_HOME or will search
+    for nvcc. Returns NVCC executable, cuda major version and cuda home directory.
+    """
+    cuda_path = None
+    CUDA_HOME = None
+
     CUDA_HOME = os.getenv('CUDA_HOME', '/usr/local/cuda')
     if not os.path.exists(CUDA_HOME):
         # We use nvcc path on Linux and cudart path on macOS
-        osname = platform.system()
-        if osname == 'Linux':
-            cuda_path = find_nvcc()
-        else:
         cudart_path = ctypes.util.find_library('cudart')
         if cudart_path is not None:
             cuda_path = os.path.dirname(cudart_path)
-            else:
-                cuda_path = None
         if cuda_path is not None:
             CUDA_HOME = os.path.dirname(cuda_path)
+            
+    if not cuda_path and not CUDA_HOME:
+        nvcc_path = find('/usr/local/', re.compile("nvcc").search, False)
+        if nvcc_path:
+            CUDA_HOME = os.path.dirname(nvcc_path)
+            if CUDA_HOME:
+                os.path.dirname(CUDA_HOME)
+
+        if (not os.path.exists(CUDA_HOME+os.sep+"lib64")
+            or not os.path.exists(CUDA_HOME+os.sep+"include") ):
+            raise RuntimeError("Error: found NVCC at ", nvcc_path ," but could not locate CUDA libraries"+
+                               " or include directories.")
+        
+        raise RuntimeError("Error: Could not find cuda on this system."+
+                           " Please set your CUDA_HOME enviornment variable to the CUDA base directory.")
+    
+    NVCC = find(CUDA_HOME, re.compile('nvcc').search)
+    CUDA_LIB = find(CUDA_HOME, re.compile('libcudart.so.*.*.*').search)
+    if CUDA_LIB:
+        try:
+            CUDA_VERSION = int(CUDA_LIB.split('.')[2])
+        except (ValueError, TypeError):
+            CUDA_VERSION = 9
     else:
-            CUDA_HOME = None
-    WITH_CUDA = CUDA_HOME is not None
-    return CUDA_HOME
+         CUDA_VERSION = 9   
+
+    if CUDA_VERSION < 8:
+        raise RuntimeError("Error: APEx requires CUDA 8 or newer")
+
+    
+    return NVCC, CUDA_VERSION, CUDA_HOME
 
 #Get some important paths
 curdir = os.path.dirname(os.path.abspath(inspect.stack()[0][1]))
@@ -87,7 +123,7 @@ extra_compile_args = ["--std=c++11",]
 
 #findcuda returns root dir of CUDA
 #include cuda/include and cuda/lib64 for python module build.
-CUDA_HOME=findcuda()
+NVCC, CUDA_VERSION, CUDA_HOME=findcuda()
 library_dirs.append(os.path.join(CUDA_HOME, "lib64"))
 include_dirs.append(os.path.join(CUDA_HOME, 'include'))
 
@@ -107,19 +143,22 @@ class RMBuild(clean):
             shutil.rmtree(eggdir)
         clean.run(self)
 
-def CompileCudaFiles():
+def CompileCudaFiles(NVCC, CUDA_VERSION):
 
         print()
         print("Compiling cuda modules with nvcc:")
+        gencodes =  ['-gencode', 'arch=compute_52,code=sm_52',
+                    '-gencode', 'arch=compute_60,code=sm_60',
+                    '-gencode', 'arch=compute_61,code=sm_61',]
+        
+        if CUDA_VERSION > 8:
+            gencodes += ['-gencode', 'arch=compute_70,code=sm_70',
+                         '-gencode', 'arch=compute_70,code=compute_70',]
         #Need arches to compile for. Compiles for 70 which requires CUDA9
-        nvcc_cmd = ['nvcc', 
+        nvcc_cmd = [NVCC, 
                        '-Xcompiler', 
-                    '-fPIC',
-                    '-gencode', 'arch=compute_52,code=sm_52',
-                    '-gencode', 'arch=compute_60,code=sm_60',
-                    '-gencode', 'arch=compute_61,code=sm_61',
-                    '-gencode', 'arch=compute_70,code=sm_70',
-                    '-gencode', 'arch=compute_70,code=compute_70',
+                       '-fPIC'
+                   ] + gencodes + [
                        '--std=c++11',
                        '-O3',
                    ]
@@ -152,7 +191,7 @@ if 'clean' not in sys.argv:
     print("library_dirs: ", library_dirs)
     print("libraries: ", main_libraries)
     print()
-    CompileCudaFiles()
+    CompileCudaFiles(NVCC, CUDA_VERSION)
 
     print("Building CUDA extension.")