Some problems occurred in the solution

Each time the program runs, the speed is very slow, and the following happens
Error umpfack umfpack_zl_symbolic status -1
Error umpfack umfpack_zl_numeric status -4
Error umfpack_di_solve status -3

The error is
#define UMFPACK_ERROR_out_of_memory (-1)

This is with why it is so slow.

Thank you, professor. Is there any solution to this problem?

load “UMFPACK64”;

problem kg2(psai2,u,solver=“UMFPACK64”)=

I can’t tell the cause of the error. Is there a reference book?

Using MUMPS,
load “MUMPS”

problem kg2(psai2,u,solver=sparsesolver,master=-1)=int2d(Th1)(psai2*u/(dt^2))


– Square mesh : nb vertices =40401 , nb triangles = 80000 , nb boundary edges 800
– Square mesh : nb vertices =289 , nb triangles = 512 , nb boundary edges 64
Attempting to use an MPI routine before initializing MPI

yes you are under windows so use load “MUMPS_seq” or use mpi version …

Thank you, professor.

Hi, professor?why?
(nan,nan) != (nan,nan) diff (nan,nan) => Sorry error in Optimization add: (p) int2d(Th,optimize=0)(…)
remark if you add (… , optimize=2) then you remove this check (be careful);
current line = 57
Exec error : In Optimized version
– number :1
Exec error : In Optimized version
– number :1

If you get nan (not a number) you system is not invertible so the problem of optimisation is other.

Thank you, professor. I found out,the parameter w = [0,1], but when parameter W > 0.1 during programming, the matrix is irreversible. Why? There have been articles about this equation in w = [0,1], which has a very good well posedness.