Fix the MNIST dataset url (pytorch#1256)

* fix the MNIST dataset url

* amend

Author: lancerts

cpp/tools/download_mnist.py

@@ -77,7 +77,8 @@ def main():
     try:
         for resource in RESOURCES:
             path = os.path.join(options.destination, resource)
-            url = 'http://yann.lecun.com/exdb/mnist/{}'.format(resource)
+            # url = 'http://yann.lecun.com/exdb/mnist/{}'.format(resource)
+            url = 'https://ossci-datasets.s3.amazonaws.com/mnist/{}'.format(resource)
             download(path, url, options.quiet)
             unzip(path, options.quiet)
     except KeyboardInterrupt:

run_cpp_examples.sh

@@ -157,10 +157,8 @@ function run_all() {
   autograd
   custom-dataset
   regression
-  
-  # dataset 503 error on yanns site
-  # dcgan
-  # mnist
+  dcgan
+  mnist
 
 }