Troubleshooting¶

In the following we will try to keep a list of the various issues and fixes that might occur during or after installation.

After a successful installation, please use the following command to verify that the extension can be loaded:

python -c "import cpymad.libmadx as l; l.start()"

The MAD-X banner should appear.

MAD-X build errors ¶

mad_main.c: undefined reference to ‘madx_start’¶

If you see an error like this:

[ 96%] Linking CXX executable madx
/usr/bin/ld: CMakeFiles/madxbin.dir/mad_main.c.o: in function `mad_init'
mad_main.c:(.text+0x44): undefined reference to `madx_start'
/usr/bin/ld: CMakeFiles/madxbin.dir/mad_main.c.o: in function `mad_run'
mad_main.c:(.text+0x73): undefined reference to `madx_input'
/usr/bin/ld: CMakeFiles/madxbin.dir/mad_main.c.o: in function `mad_fini'
mad_main.c:(.text+0x81): undefined reference to `madx_finish'
/usr/bin/ld: CMakeFiles/madxbin.dir/mad_main.c.o: in function `main'
mad_main.c:(.text.startup+0xc): undefined reference to `madx_input'
/usr/bin/ld: mad_main.c:(.text.startup+0x11): undefined reference to `madx_finish'
/usr/bin/ld: mad_main.c:(.text.startup+0x16): undefined reference to `geterrorflag_'

It probably means that you attempted to build MAD-X as shared object -DBUILD_SHARED_LIBS=ON with -DCMAKE_C_FLAGS="-fvisibility=hidden". If that is the case, either build MAD-X with -DBUILD_SHARED_LIBS=OFF, or change hidden to protected, or leave out the visibility option entirely.

Fatal Error: Cannot open module file ‘gxx11_common.mod’¶

With some compiler toolchains (manylinux2014) the following error has been observed, followed by some additional outputs and warnings:

/mnt/MAD-X/src/gxx11ps.f90:2:7:

    2 |   use gxx11_common
      |       1
Fatal Error: Cannot open module file ‘gxx11_common.mod’ for reading at (1): No such file or directory
compilation terminated.
make[2]: *** [src/CMakeFiles/madx.dir/build.make:101: src/CMakeFiles/madx.dir/gxx11ps.f90.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[...]
make[1]: *** [CMakeFiles/Makefile2:1356: src/CMakeFiles/madx.dir/all] Error 2
make: *** [Makefile:166: all] Error 2

This is likely related to using parallel make jobs, i.e. make -j. If that’s the case for you, try without -j.

Setup or compile time errors ¶

Errors that occur during the execution of pip install cpymad or python setup.py build.

ERROR: No matching distribution found ¶

Problem: pip install cpymad fails with either or both of these messages:

ERROR: Could not find a version that satisfies the requirement cpymad
ERROR: No matching distribution found for cpymad

This usually means that we haven’t uploaded wheels for your platform or python version. In this case, either ping us about adding a corresponding wheel, or refer to the platform specific Installation Instructions.

fatal error: `madX/mad_types_f.h`: No such file or directory ¶

Problem: pip install cpymad fails and shows an error similar to the following:

gcc [...] -c src/cpymad/libmadx.c [...]
src/cpymad/libmadx.c:642:10: fatal error: madX/mad_types_f.h: No such file or directory
  642 | #include "madX/mad_types_f.h"
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
error: command 'gcc' failed with exit status 1
----------------------------------------
ERROR: Command errored out with exit status 1: [...]

This occurs because pip couldn’t find a prebuilt binary wheel that is compatible with your platform, and tried to build the source distribution instead. Please ping us about adding a wheel for your platform or refer to the Building from source guide.

OSError: Missing source file ¶

Message:

OSError: Missing source file: 'cpymad/libmadx.c'. Install Cython to resolve this problem.

This can occur if building cpymad from a local checkout without having Cython installed. The solution is to install cython and try again:

pip install cython

Runtime errors ¶

Errors that occur after a successful installation when trying to use cpymad.

ImportError: undefined symbol: _ZGVbN2vv_pow ¶

There are several possible fixes:

The simplest fix that works without rebuilding MAD-X is to link cpymad against libmvec. This can be done by passing -lm to the python setup.py build_ext -lm command. You can also pass it through pip as follows pip install -e . --global-option build_ext --global-option -lm. This fix is the recommended one when building for local use on your own machine.
Rebuild MAD-X without vectorization optimizations by passing -DCMAKE_C_FLAGS="-fno-tree-vectorize". Same for CMAKE_CXX_FLAGS, and CMAKE_Fortran_FLAGS.
Rebuild MAD-X in Debug mode (where these optimizations are disabled by default)
Rebuild MAD-X as shared object: -DBUILD_SHARED_LIBS=ON (also remove -fvisibility or change to protected), and run setup.py with export SHARED=1.
use a manylinux build of cpymad

ImportError: undefined symbol: dgelsd_¶

Message:

ImportError: [...]/cpymad/libmadx.so: undefined symbol: dgelsd_

This message is the result of linking cpymad’s libmadx extension module without a required dependency. In the specific case above, it means that MAD-X was built with BLAS/LAPACK, but cpymad was not linked against these libraries. The cpymad setup currently has no mechanism to detect with which libraries MAD-X was built and assumes by default only some standard libraries.

Possible solutions are either rebuilding MAD-X without BLAS/LAPACK, or passing appropriate libraries during the cpymad build step. The latter can be done by through environment variables:

export BLAS=1
export LAPACK=1
pip install .

Or by passing linker flags to the setup.py build_ext command manually:

python setup.py build_ext -lblas -llapack

ImportError: libmadx.so ¶

Message:

ImportError: libmadx.so: cannot open shared object file: No such file or directory

This error can have multiple causes. It often means that cpymad is linked against one or more dynamic libraries that could not be found at runtime. Reasons may be that the MAD-X installation was moved or removed after building cpymad.

A possible solution is to use a permanent installation directory for MAD-X and specify this during the build:

export MADXDIR=<madx-install-prefix>
pip install .

Another possible solution is to specify the appropriate RPATH to the setup script when building:

python setup.py build_ext --rpath=<rpath>
python setup.py install

Here, <madx-install-prefix> is the base folder containing the subfolders bin, include, lib of the MAD-X build and <rpath> contains the dynamic library files.

If this does not work, you can set the LD_LIBRARY_PATH (or DYLD_LIBRARY_PATH on OSX) environment variable before running pymad, for example:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$HOME/.local/lib/