MATLAB: LAPACK error: info -5

lapacksimulink

Hi All,
I'm getting an error when running a Simulink model. I'm not sure what its from. As far as I know I'm not specifically calling out an use of LAPACK. Any insight into possible causes would be great!
Thanks
An error occurred while running the simulation and the simulation was terminated Caused by: The LAPACK call to 'LAPACKE_zgeev' failed with info -5. Please contact MathWorks Technical Support if you can reproduce this error.

Best Answer

BLAS and LAPACK are the math libraries that MATLAB uses for linear algebra. zgeev is the name of one of the routines in the LAPACK library. E.g., a description can be found on netlib.org (showing Fortran code although the actual libraries that MATLAB uses are likely highly optimized C/assembly using the same interface):
http://www.netlib.org/lapack/explore-3.1.1-html/zgeev.f.html
If you look at the comments for this routine, you see this for "info":
*  INFO    (output) INTEGER
*          = 0:  successful exit
*          < 0:  if INFO = -i, the i-th argument had an illegal value.
*          > 0:  if INFO = i, the QR algorithm failed to compute all the
*                eigenvalues, and no eigenvectors have been computed;
*                elements and i+1:N of W contain eigenvalues which have
*                converged.
So it appears that the 5th argument had an illegal value. If you look at the signature and the code for generating the error you see this:
      SUBROUTINE ZGEEV( JOBVL, JOBVR, N, A, LDA, W, VL, LDVL, VR, LDVR,
     $                  WORK, LWORK, RWORK, INFO )
                 :
  *  ZGEEV computes for an N-by-N complex nonsymmetric matrix A, the
  *  eigenvalues and, optionally, the left and/or right eigenvectors.
                 :
      ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
         INFO = -5
So the 5th input argument, LDA, was less than MAX(1,N), generating the error. Based on nothing more than what you have posted, this looks like a bug in the calling routine. So technical support needs to look at the underlying code that is generating this call.
Is there something unusual about the inputs you are using for your apparent eigenvalue calculations? E.g., if LDA = 0 then this would generate this error. And if you look at what LDA is in the code:
        COMPLEX*16         A( LDA, * ), VL( LDVL, * ), VR( LDVR, * ),
       $                   W( * ), WORK( * )
You see that it is the first dimension of one of the input arrays. Are you passing in (i.e. trying to compute the eigenvalues of) a matrix with this first dimension equal to 0?
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