Assertions and error checking

AMReX assert macros

AMReX provides several assertion macros:

• AMREX_ASSERT: Enabled when either -DAMREX_DEBUG or -DAMREX_USE_ASSERTION is defined. When enabled, it calls amrex::Assert() which will abort unless both -DNDEBUG is defined AND -DAMREX_USE_ASSERTION is NOT defined. This means:
  • The macro itself is a no-op when neither AMREX_DEBUG nor AMREX_USE_ASSERTION is defined
  • When the macro is enabled and assertion fails, it will abort unless NDEBUG is defined without AMREX_USE_ASSERTION
• AMREX_ALWAYS_ASSERT: Always calls amrex::Assert() regardless of build configuration. The actual abort behavior follows the same rules as AMREX_ASSERT - it will abort unless both -DNDEBUG is defined AND -DAMREX_USE_ASSERTION is NOT defined. Note that CMake adds "-DNDEBUG" by default when "CMAKE_BUILD_TYPE=Release". (See this GitHub discussion for details.)

Abort

Because the default CMake flags added in Release mode causes AMREX_ALWAYS_ASSERT not to function in GPU code, amrex::Abort is the best option to use if you want to abort a GPU kernel.

amrex::Abort requires additional GPU register usage, so it should be used sparingly. The best strategy for error handling is often to set a value in an array that indicates an iterative solve failed in a given cell. (This is what Castro does for its nuclear burning networks.)

For more details, see the AMReX documentation on assertions and error checking.