Frequently asked question

Configuration with Cmake

Cmake fails with “CMake wants to use -std=c++1z which is not supported by NVCC” when configuring with Cuda: This error happens when cmake detects an old version of gcc (<=7). These old version uses -std=c++1z to enable c++17, but this flag is not recognised by Cuda nvcc compiler. Use a more recent version of gcc (>=8).
Cmake fails with “C++17-compliant compiler detected, but unable to compile C++14 or later program. Verify that Intel:xxxxxxxxx is set up correctly” when using intel compilers: The error arises with some error on the “std” namespace,. This is because the intel compiler tries to use the default GNU C++ Headers, and these are too old. Try to install a more recent release of the gcc compilation suite.
How do I use my favourite XXXXX compiler?: set the CXX variables to your favourite C++ compiler before calling Cmake (see Main configuration options). Do not forget to delete any CmakeCache.txt which could have been produced in your problem directory.
I have a complex setup, and have written some functions in separate .cpp files. How can I add these files to Idefix build tree?: Add a CmakeLists.txt in your problem directory and use the function add_idefix_source (see Add/replace custom source files).

Is there a way to see explicitely the compilation commands with make?: Yes, just add VERBOSE=1 after the make command.
The compilation stops while compiling Kokkos with /usr/include/stdlib.h(58): error: expected a ";": This happens on Gricad machines when LIBDL is activated (wrong glibc). Simply disable LIBDL.

How can I stop the code without loosing the current calculation?: Two options: the simplest one is to create an empty file named stop in the running directory (e.g. with touch stop). It is also possible to send the POSIX signal SIGUSR2 to one of the idefix processes. More details here: Signal Handling.
I’m doing performance measures. How do I disable all outputs in Idefix?: Add -nowrite when you call Idefix executable.

I have a serious bug (e.g. segmentation fault), in my setup, how do I proceed?: Add -DIdefix_DEBUG=ON to cmake and recompile to find out exactly where the code crashes.
I want to test a modification to Idefix source code specific to my problem without modifying files in $IDEFIX_DIR. How can I proceed?: Add a CmakeLists.txt in your problem directory and use the function replace_idefix_source (see Add/replace custom source files).
I want to use a lookup table from a CSV file in my idefix_loop. How could I proceed?: Use the LookupTable class (see LookupTable class)