This test also can hang in a loop.

src/mlpack/tests/main_tests/lmnn_test.cpp

@@ -118,7 +118,9 @@ BOOST_AUTO_TEST_CASE(LMNNOptimizerTest)
   // Input random data points.
   SetInputParam("input", inputData);
   SetInputParam("labels", labels);
-  SetInputParam("optimizer",  std::string("bbsgd"));
+  // TODO: set back to bbsgd---this was done for #1490 and should be reverted
+  // when that is fixed.
+  SetInputParam("optimizer",  std::string("amsgrad"));
 
   mlpackMain();