Using the contents of arma_config.hpp, try to catch the condition where the user has included mlpack with ARMA_64BIT_WORD enabled but mlpack was compiled without ARMA_64BIT_WORD enabled. This should help prevent a long, drawn-out debugging process where nobody can figure out why the stack is getting mangled.
mlpack is free software; you may redistribute it and/or modify it under the terms of the 3-clause BSD license. You should have received a copy of the 3-clause BSD license along with mlpack. If not, see http://www.opensource.org/licenses/BSD-3-Clause for more information.
Definition in file arma_config_check.hpp.