In a large code base, I split my large matrices in blocks. It can happen that there is a 1x1 matrix block that will be solved in the same general way, using pardiso. However, since 2025 I get an out of memory error in this case.
Is this a known issue, or should I change settings to avoid this?
The following small example gives me a -2 error.
program pardiso_example
use, intrinsic :: iso_fortran_env, only: wp => real64
implicit none
integer :: ia(2), ja(1)
real(wp) :: a(1), b(1), x(1)
integer :: nnz, phase, maxfct, mnum, error, msglvl
integer :: iparm(64)
integer(kind=8) :: pt(64)
integer, parameter :: mtype = 11 ! Real unsymmetric matrix
! Fill a tiny dense matrix
ia(1) = 1
ia(2) = 2
a(1) = 2.0_wp
b(1) = 1.0_wp
ja(1) = 1
! Initialize PARDISO control parameters
pt = 0
iparm = 0
iparm(1) = 1 ! No default values
iparm(2) = 2 ! Fill-in reordering from METIS
iparm(3) = 0 ! No iterative-direct algorithm
iparm(4) = 0 ! No user fill-in reducing permutation
iparm(5) = 0 ! Write solution into x
iparm(7) = 2 ! Max number of iterative refinement steps
iparm(9) = 13 ! Perturb the pivot elements with 1E-13
iparm(10) = 1 ! Use nonsymmetric permutation and scaling MPS
iparm(11) = 0 ! Not available
iparm(13) = 0 ! Output: Number of perturbed pivots
iparm(17) = -1 ! Output: Number of nonzeros in factors
iparm(18) = -1 ! Output: Mflops for LU factorization
iparm(19) = 0 ! Output: Numbers of CG Iterations
maxfct = 1
mnum = 1
msglvl = 0
error = 0
! Factorization and solve
phase = 13
x = b
call pardiso(pt, maxfct, mnum, mtype, phase, 1, a, ia, ja, 0, 1, iparm, msglvl, b, x, error)
if (error /= 0) then
print *, "PARDISO error:", error
end if
print *, "Solution x:"
print *, x
end program pardiso_example
