Update Makefile.rule

Makefile.rule

@@ -61,10 +61,10 @@ VERSION = 0.3.0.dev
 # NUM_THREADS = 24
 
 # If you have enabled USE_OPENMP and your application would call
-# OpenBLAS's caculation API in multi threads, please comment it in.
-# This flag define how many OpenBLAS's caculation API can actually
-# run in parallel. If more number threads call OpenBLAS's caculation API,
-# it would wait former API finish.
+# OpenBLAS's calculation API from multi threads, please comment it in.
+# This flag defines how many instances of OpenBLAS's calculation API can 
+# actually run in parallel. If more threads call OpenBLAS's calculation API,
+# they need to wait for the preceding API calls to finish or risk data corruption.
 # NUM_PARALLEL = 2
 
 # if you don't need to install the static library, please comment it in.