Fix ctc_enabled detection and correct headers and library paths of CTC Ops

theano/gpuarray/ctc.py

@@ -50,15 +50,18 @@ class GpuConnectionistTemporalClassification(gof.COp):
         gof.COp.__init__(self, self.func_file, self.func_name)
 
     def c_lib_dirs(self):
-        assert ctc_available.path is not None
-        return [ctc_available.path]
+        lib_dirs = []
+        if ctc_available.path is not None:
+            lib_dirs += [ctc_available.path]
+        return lib_dirs
 
     def c_libraries(self):
         return ["warpctc", "gpuarray"]
 
     def c_header_dirs(self):
         dirs = [os.path.dirname(__file__), pygpu.get_include()]
-        dirs.append(os.path.join(config.ctc.root, "include"))
+        if config.ctc.root != '':
+            dirs.append(os.path.join(config.ctc.root, "include"))
         return dirs
 
     def c_headers(self):

theano/tensor/nnet/ctc.py

@@ -39,9 +39,9 @@ options.loc = CTC_CPU;
 options.num_threads = 1;
 """
 
-    params = ["-I%s" % (os.path.join(config.ctc.root, "include"))]
-    params.extend(['-I%s' % (os.path.dirname(__file__))])
+    params = ['-I%s' % (os.path.dirname(__file__))]
     if ctc_lib_path is not None:
+        params.extend(["-I%s" % (os.path.join(config.ctc.root, "include"))])
         params.extend(["-L%s" % (ctc_lib_path)])
     params.extend(["-l", "warpctc"])
     compiler_res = GCC_compiler.try_flags(
@@ -70,12 +70,7 @@ ctc_present.path = None
 
 
 def ctc_available():
-    if config.ctc.root == '':
-        ctc_available.msg = 'ctc.root variable is not set, please set it ',
-        'to the root directory of the CTC library in ',
-        'your system.'
-        return False
-    elif os.name == 'nt':
+    if os.name == 'nt':
         ctc_available.msg = 'Windows platforms are currently not supported ',
         'by underlying CTC library (warp-ctc).'
         return False
@@ -127,16 +122,21 @@ class ConnectionistTemporalClassification(gof.COp, gof.OpenMPOp):
         self.default_output = 0
 
     def c_lib_dirs(self):
-        assert ctc_available.path is not None
-        return [ctc_available.path]
+        lib_dirs = []
+        if ctc_available.path is not None:
+            lib_dirs += [ctc_available.path]
+        return lib_dirs
 
     def c_libraries(self):
         return ["warpctc"]
 
     def c_header_dirs(self):
-        # We assume here that the header is available at the include directory
-        # of the CTC root directory.
-        return [os.path.join(config.ctc.root, "include")]
+        header_dirs = []
+        if config.ctc.root != '':
+            # We assume here that the header is available at the include directory
+            # of the CTC root directory.
+            header_dirs += [os.path.join(config.ctc.root, "include")]
+        return header_dirs
 
     def c_compile_args(self):
         return gof.OpenMPOp.c_compile_args(self)