[petsc-users] New nonzero caused a malloc

[Luca Verzeroli]

Good mornig,

I'm new to PETSc and i'm wondering about this problem.

When i run my code with 2 processes I have no problem. When i use more 
than 2 processes I receive this message:

[1]PETSC ERROR: --------------------- Error Message 
--------------------------------------------------------------
[1]PETSC ERROR: Argument out of range
[1]PETSC ERROR: New nonzero at (0,43) caused a malloc
Use MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE) to turn 
off this check

This means that a process is trying to write in cell (0,43)?

Then I try with MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, 
PETSC_FALSE) and I

check with MatView if there's an element in (0,43) but nothing is 
written there.

Otherwise, I have checked the index I use to insert element in the 
matrix but no (0,43) is present.


Could you give me some advices about the possible solution of this problem?

Luca