@balos1 I am able to compile and run with both sundials 6 and 7 using gnu make. But there are still some issues with cmake. SUNDIALS::core is only available in v7. So I made it an optional component and check if it's found after find_package is called. But I got the following error,

CMake Error at Tools/CMake/AMReXThirdPartyLibraries.cmake:148 (find_package):
  Could not find a configuration file for package "SUNDIALS" that is
  compatible with requested version "6.0.0".

  The following configuration files were considered but not accepted:

    /home/wqzhang/mygitrepo/spack/opt/spack/linux-ubuntu20.04-skylake/gcc-9.4.0/sundials-develop-5wskgac5smdxvywok7yuojfsk6jfzr6a/lib/cmake/sundials/SUNDIALSConfig.cmake, version: 7.0.0

Is version 7.0.0 considered incompatible with 6.0.0 in the sundials' cmake config file? If we want to support both v7 and v6, how should we handle this?

@ax3l

Note that if I simply set the minimum version to 7.0.0 with core as optional, it works.

@WeiqunZhang Unfortunately it looks like we setup the CMake version file for SUNDIALS with the SameMajorVersion compatibility mode. Im going to change it to AnyNewerVersion, but that doesn't fix the problem for 7.0.0. The workaround is to either do find_package twice (once with minimum 6.0.0 and once with minimum 7.0.0, check if NOT SUNDIALS_FOUND after the first one), or check the version manually like this:

find_package(SUNDIALS CONFIG REQUIRED
                      COMPONENTS ${SUNDIALS_COMPONENTS}
                      OPTIONAL_COMPONENTS core)
set(SUNDIALS_MINIMUM_VERSION 6.0.0)
if (SUNDIALS_VERSION VERSION_LESS ${SUNDIALS_MINIMUM_VERSION})
   message(FATAL_ERROR "SUNDIALS ${SUNDIALS_MINIMUM_VERSION} or newer is required. Found version ${SUNDIALS_VERSION}.")
endif()