Suggest default CUDA/cuDNN/TensorRT versions after initial auto-detection.

Reduce spew on error message when some file was not found.

PiperOrigin-RevId: 243810113
diff --git a/configure.py b/configure.py
index fe0e6d7..1a69b06 100644
--- a/configure.py
+++ b/configure.py
@@ -33,6 +33,9 @@
   from distutils.spawn import find_executable as which
 # pylint: enable=g-import-not-at-top
 
+_DEFAULT_CUDA_VERSION = '10'
+_DEFAULT_CUDNN_VERSION = '7'
+_DEFAULT_TENSORRT_VERSION = '5'
 _DEFAULT_CUDA_COMPUTE_CAPABILITIES = '3.5,7.0'
 
 _TF_OPENCL_VERSION = '1.2'
@@ -865,21 +868,25 @@
 
 def set_tf_cuda_version(environ_cp):
   """Set TF_CUDA_VERSION."""
-  ask_cuda_version = ('Please specify the CUDA SDK version you want to use. '
-                      '[Leave empty to accept any version]: ')
+  ask_cuda_version = (
+      'Please specify the CUDA SDK version you want to use. '
+      '[Leave empty to default to CUDA %s]: ') % _DEFAULT_CUDA_VERSION
   tf_cuda_version = get_from_env_or_user_or_default(environ_cp,
                                                     'TF_CUDA_VERSION',
-                                                    ask_cuda_version, '')
+                                                    ask_cuda_version,
+                                                    _DEFAULT_CUDA_VERSION)
   environ_cp['TF_CUDA_VERSION'] = tf_cuda_version
 
 
 def set_tf_cudnn_version(environ_cp):
   """Set TF_CUDNN_VERSION."""
-  ask_cudnn_version = ('Please specify the cuDNN version you want to use. '
-                       '[Leave empty to accept any version]: ')
+  ask_cudnn_version = (
+      'Please specify the cuDNN version you want to use. '
+      '[Leave empty to default to cuDNN %s]: ') % _DEFAULT_CUDNN_VERSION
   tf_cudnn_version = get_from_env_or_user_or_default(environ_cp,
                                                      'TF_CUDNN_VERSION',
-                                                     ask_cudnn_version, '')
+                                                     ask_cudnn_version,
+                                                     _DEFAULT_CUDNN_VERSION)
   environ_cp['TF_CUDNN_VERSION'] = tf_cudnn_version
 
 
@@ -922,11 +929,10 @@
 
   ask_tensorrt_version = (
       'Please specify the TensorRT version you want to use. '
-      '[Leave empty to accept any version]: ')
-  tf_tensorrt_version = get_from_env_or_user_or_default(environ_cp,
-                                                        'TF_TENSORRT_VERSION',
-                                                        ask_tensorrt_version,
-                                                        '')
+      '[Leave empty to  default to TensorRT %s]: ') % _DEFAULT_TENSORRT_VERSION
+  tf_tensorrt_version = get_from_env_or_user_or_default(
+      environ_cp, 'TF_TENSORRT_VERSION', ask_tensorrt_version,
+      _DEFAULT_TENSORRT_VERSION)
   environ_cp['TF_TENSORRT_VERSION'] = tf_tensorrt_version
 
 
@@ -1331,7 +1337,7 @@
 
   if proc.wait():
     # Errors from find_cuda_config.py were sent to stderr.
-    print('\n\nAsking for detailed CUDA configuration...\n')
+    print('Asking for detailed CUDA configuration...\n')
     return False
 
   config = dict(