fortran-lang/stdlib

"double free or corruption (out)" when requesting eigenvectors in complex generalized eigenvalue problem

edvinolo opened this issue · 1 comments

edvinolo commented

Description

Calling the eig subroutine for a generalized eigenvalue problem with complex A and B matrices leads to a memory fault when right or left eigenvectors are requested. The error seems to only occur for this specific combination, if I change A and B to real, or remove the optional left and right eigenvector arguments there are no problems.

Here is a reproducer:

program test
  use stdlib_linalg, only: eig
  implicit none

  double complex, dimension(3,3) :: A_Z,S_Z
  double precision, dimension(3,3) :: A_D,S_D
  double complex, dimension(3,3) :: vecs_r
  double complex,dimension(3) :: eigs
  integer :: i

  ! Set matrix
  A_Z = reshape( [ [1, 6, 3], &
                 [9, 2, 1], &
                 [8, 3, 4] ], [3,3] )

  S_Z = 0
  do i= 1,3
    S_Z(i,i) = i
  end do

  A_D = real(A_Z)
  S_D = real(S_Z)

  call eig(A_D,S_D,eigs,right=vecs_r) !Works
  call eig(A_Z,S_Z,eigs,right=vecs_r) !Fails
  write(6,*) eigs

end program test

and here is the error message and backtrace:

double free or corruption (out)

Program received signal SIGABRT: Process abort signal.

Backtrace for this error:
#0  0x7f0809780d11 in ???
#1  0x7f080977fee5 in ???
#2  0x7f08093d108f in ???
	at /build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
#3  0x7f08093d100b in __GI_raise
	at ../sysdeps/unix/sysv/linux/raise.c:51
#4  0x7f08093b0858 in __GI_abort
	at /build/glibc-LcI20x/glibc-2.31/stdlib/abort.c:79
#5  0x7f080941b26d in __libc_message
	at ../sysdeps/posix/libc_fatal.c:155
#6  0x7f08094232fb in malloc_printerr
	at /build/glibc-LcI20x/glibc-2.31/malloc/malloc.c:5347
#7  0x7f0809424f9f in _int_free
	at /build/glibc-LcI20x/glibc-2.31/malloc/malloc.c:4314
#8  0x556798caef27 in ???
#9  0x556798c98f6c in test
	at /home/edvinolofsson/stdlib_gen_eig_bug/test.f90:25
#10  0x556798c99092 in main
	at /home/edvinolofsson/stdlib_gen_eig_bug/test.f90:2
Aborted (core dumped)

Expected Behaviour

The call to eig should return the eigenvalues and eigenvectors also for complex A and B.

Version of stdlib

8916fc5

Platform and Architecture

Ubuntu 20.04, x86 , gfortran 10.5.0 (but can reproduce it also on compiler explorer with latest gfortran)

Additional Information

compiler explorer link: https://godbolt.org/z/bYW6v6jso

perazz commented

I copied the actual routines running your example at https://godbolt.org/z/T8TT1nsx4

It looks like there is insufficient work size for rwork.

Rwork is initialized at 2*n which is OK for the standard problem (GEEV) but not for the generalized problem (GGEV), that wants 8*n

I have overlooked that when implementing generalized eigs, will deploy a fix soon

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