[Octave-bug-tracker] [bug #49235] test inv crashes when compiled with Intel compiler

[Dario Meluzzi]

Follow-up Comment #2, bug #49235 (project octave):

I encountered the same problem when running make check with octave-4.2.1
compiled on Ubuntu 14.04. Also running inv([1 2;3 4]) at the command line
crashes the program with a similar stack trace. I investigated the problem and
found the cause to be an insufficiently large work array passed to LAPACK
subroutines dgecon and sgecon when they called in files
liboctave/array/[df]Matrix.cc. In fact there are four calls to those
subroutines in each of those files. Three of the calls pass a work array of
the correct size, while the remaining call does not. As stated in the
subroutine definitions (see for example
https://fossies.org/linux/OpenBLAS/lapack-netlib/SRC/dgecon.f), the size of
the work array must be 4*N, where N is the order of the matrix, but the faulty
calls pass an array of size 2*N.
The fix is trivial.

diff octave-4.2.1-bugs/liboctave/array/dMatrix.cc
octave-4.2.1/liboctave/array/dMatrix.cc
549c549
<   lwork = (lwork < 2 *nc ? 2*nc : lwork);
---
>   lwork = (lwork < 4 *nc ? 4*nc : lwork);
diff octave-4.2.1-bugs/liboctave/array/fMatrix.cc
octave-4.2.1/liboctave/array/fMatrix.cc
555c555
<   lwork = (lwork < 2 *nc ? 2*nc : lwork);
---
>   lwork = (lwork < 4 *nc ? 4*nc : lwork);


(file #41029)
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