[petsc-dev] Mat updating from 3.7 to 3.9.2 Fortran

[Jed Brown]

Hector E Barrios Molano <hectorb at utexas.edu> writes:

> Hi PETSc Experts!
>
> I am updating a Fortran code that use PETSc 3.7 to version 3.9.2 (from 
> git repository).
>
> Such code declares:
>
> Mat mat
>
> and used it as an integer, for example, to assign an initial value and 
> test it to know if the matrix has been created by PETSc.
>
> data mat/-1/
> if (mat .eq. -1) then

You can use PETSC_NULL_MAT

> With the new PETSc Fortran modules the compiler complains about this and 
> stops.
>
> Is there a better way to achieve this? So that I do not have to set an 
> predefined value to Mat type to test if it was already created by PETSc?
>
> If not, Is there a way to access the value in mat?
> Looking at the source code type(tMat) has "v" variable, so could I used 
> as mat%v?

Please no.