Raise min cudnn version to v4. Better report of the problem when not used.

theano/sandbox/cuda/__init__.py

@@ -270,14 +270,14 @@ from theano.sandbox.cuda.type import CudaNdarrayType
 def dnn_available():
     if config.dnn.enabled == "False":
         dnn_available.avail = False
-        dnn_available.msg = "disabled by dnn.enabled flag"
+        dnn_available.msg = "Disabled by dnn.enabled flag"
     if dnn_available.avail is None and not cuda_available:
         dnn_available.msg = "CUDA not available"
         dnn_available.avail = False
     elif dnn_available.avail is None:
         dev = active_device_number()
         if device_properties(dev)['major'] < 3:
-            dnn_available.msg = "Device not supported by cuDNN"
+            dnn_available.msg = "Device not supported"
             dnn_available.avail = False
         else:
             preambule = """
@@ -315,7 +315,7 @@ if ((err = cudnnCreate(&_handle)) != CUDNN_STATUS_SUCCESS) {
             dnn_available.avail = comp
             if not dnn_available.avail:
                 dnn_available.msg = (
-                    "Theano can not compile with cuDNN. We got this error:\n" +
+                    "Can not compile with cuDNN. We got this error:\n" +
                     str(err))
             else:
                 # If we can compile, check that we can import and run.
@@ -326,13 +326,10 @@ if ((err = cudnnCreate(&_handle)) != CUDNN_STATUS_SUCCESS) {
                                          " from one version, but we link with"
                                          " a different version %s" % str(v))
                     raise RuntimeError(dnn_available.msg)
-                if v == -1 or v[0] < 3007:
-                    # 3007 is the final release of cudnn v3
+                if v == -1 or v[0] < 4007:
+                    # 4007 is the final release of cudnn v4
                     dnn_available.avail = False
-                    dnn_available.msg = (
-                        "You have an old release of CuDNN (or a release "
-                        "candidate) that isn't supported.  Please update to "
-                        "at least v3 final version.")
+                    dnn_available.msg = "Version too old. Update to v5."
                     raise RuntimeError(dnn_available.msg)
     if config.dnn.enabled == "True":
         if not dnn_available.avail:
@@ -582,13 +579,13 @@ def use(device,
                     if dnn_available():
                         (hdr_v, runtime_v) = dnn_version()
                         cudnn_version = runtime_v
-                        # 4100 should not print warning with cudnn 4 final.
-                        if cudnn_version > 4100:
+                        # 5100 should not print warning with cudnn 5 final.
+                        if cudnn_version > 5100:
                             warn = ("Your CuDNN version is more recent then Theano."
                                     " If you see problems, try updating Theano or"
-                                    " downgrading CuDNN to version 4.")
+                                    " downgrading CuDNN to version 5.")
                 except Exception:
-                    pass
+                    cudnn_version = dnn_available.msg
                 print("Using gpu device %d: %s (CNMeM is %s, CuDNN %s)" % (
                     active_device_number(),
                     active_device_name(),

theano/sandbox/gpuarray/__init__.py

@@ -71,14 +71,14 @@ def init_dev(dev, name=None):
             cudnn_version = " (CuDNN not available)"
             try:
                 cudnn_version = dnn.version()
-                # 4100 should not print warning with cudnn 4 final.
-                if cudnn_version > 4100:
+                # 5100 should not print warning with cudnn 5 final.
+                if cudnn_version > 5100:
                     warn = ("Your CuDNN version is more recent than Theano."
                             " If you see problems, try updating Theano or"
-                            " downgrading CuDNN to version 4.")
+                            " downgrading CuDNN to version 5.")
                 cudnn_version = " (CuDNN version %s)" % cudnn_version
             except Exception:
-                pass
+                cudnn_version = dnn.dnn_present.msg
         print("Mapped name %s to device %s: %s%s" % (
             name, dev, context.devname, cudnn_version),
               file=sys.stderr)

theano/sandbox/gpuarray/dnn.py

@@ -74,18 +74,15 @@ if ((err = cudnnCreate(&_handle)) != CUDNN_STATUS_SUCCESS) {
         try_run=False, output=True)
 
     if not avail:
-        return False, ("Theano cannot compile with cuDNN. "
+        return False, ("cannot compile with CuDNN. "
                        "We got this error:\n" + str(err))
     return True, None
 
 
 def _dnn_check_version():
     v = version()
-    if v < 3007:
-        return False, (
-            "You have an old release of CuDNN (or a release candidate) "
-            "that isn't supported.  Please update to at least v3 final "
-            "version.")
+    if v < 4007:
+        return False, "Version too old. Update to v5."
 
     return True, None
 
@@ -94,7 +91,7 @@ def dnn_present():
     if dnn_present.avail is not None:
         return dnn_present.avail
     if config.dnn.enabled == "False":
-        dnn_present.msg = "disabled by dnn.enabled flag"
+        dnn_present.msg = "Disabled by dnn.enabled flag"
         dnn_present.avail = False
 
     if pygpu is None:
@@ -134,7 +131,7 @@ def dnn_available(context_name):
     # This is a hack because bin_id is in the from of
     # "<something>_<major><minor>" for cuda devices.
     if ctx.bin_id[-2:] < b'30':
-        dnn_available.msg = "Device not supported by cuDNN"
+        dnn_available.msg = "Device not supported"
         return False
 
     return True
@@ -1620,7 +1617,7 @@ class NoCuDNNRaise(Optimizer):
                 # just skip this optimization.
                 raise AssertionError(
                     "cuDNN optimization was enabled, but Theano was not able "
-                    "to use it for context " + c + ". We got this error: \n" +
+                    "to use it for context " + str(c) + ". We got this error: \n" +
                     dnn_available.msg)
 
 gpu_seqopt.register("NoCuDNNRaise", NoCuDNNRaise(), 0, 'cudnn')