Problem description

The latest version of MATLAB (R2024b) comes with Intel MKL as the default library for BLAS and LAPACK. This version of MKL is built with ILP64 where a 64-bit int type is used for all integers in order to support very large array sizes (>2^31-1). The default OpenBLAS package that comes with Cantera uses LP64 where standard integers are 32-bit and the long type is required for 64-bit integers. This causes an incompatibility issue when data in an array is passed back and forth between MATLAB and OpenBLAS. In some cases this will just return an incorrect type error but in the worst case scenario will cause a buffer overflow and instantly crashes MATLAB.

A partial workaround exists to resolve this problem, as mentioned in this thread. We can bypass ILP64 MKL by setting the environment variable LD_PRELOAD and force MATLAB to use the LP64 OpenBLAS library in the Cantera environment. This will correctly set the types of integers and Cantera will successfully solve any linear algebra problems. However, this workaround is unstable and will cause crashes when the plot function is invoked, for example to plot to concentration of species over time.

Steps to reproduce

1. In MATLAB, run ctLoad;
2. Run example equil.m;
3. Exit MATLAB and set LD_PRELOAD to the location of the OpenBLAS library in your Cantera environment;
4. Repeat 1) and 2).

Behavior

The gas object will fail to equilibrate, this error appears in the MATLAB terminal:

Error using ctFunc (line 11)

*******************************************************************************
CanteraError thrown by MultiPhase::equilibrate_MultiPhaseEquil:
No convergence for T
*******************************************************************************

Error in ThermoPhase/equilibrate (line 493)
            ctFunc('thermo_equilibrate', tp.tpID, xy, solver, rtol, ...
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in equil (line 39)
        gas.equilibrate('HP');
        ^^^^^^^^^^^^^^^^^^^^^

while this error will appear in the linux terminal:

Intel oneMKL ERROR: Parameter 6 was incorrect on entry to DGEMV

Parameter 6 of DGEMV is the leading dimension of a matrix, which in MKL ILP64 is a 64-bit int type but in OpenBLAS is a 64-bit long.

After setting the LD_PRELOAD variable to the correct OpenBLAS location. This example will successfully run until the plot function is invoked to plot the equivalence ratio vs. temperature. MATLAB instantly crashes and throws either a free(): invalid pointer error or munmap_chunk() error, both of which indicate a memory corruption has occured. It is unknown whether other built-in MATLAB functions will cause these crashes, but simple manipulations on the data being plotted did not return any errors or cause crashes. A crash dump info is included below:

matlab_crash_dump_510456-1.txt

System information

• Cantera version: 3.2.0
• OS: Ubuntu 22.04.5 LTS
• Python/MATLAB/other software versions: MATLAB R2024b

Additional context

Older versions of MATLAB are untested.