[petsc-users] Write Non-Zero Values of MPI Matrix on an MPI Vector

[Jed Brown]

Ali Kahraman <aliberkkahraman at yahoo.com> writes:

>   
> Dear All,
>  
> My problem definition is as follows,
>  
> I  have an MPI matrix with a random sparsity pattern i.e. I do not know how many nonzeros there are on any row unless I call MatGetRow to learn it. There are possibly unequal numbers of nonzeros on every row. I want to write all the nonzero values of this matrix onto a parallel vector. An example can be as follows. 
>  
>  
> Imagine I have a 4x4 matrix (; denotes next row, . denotes sparse "zeros") [3 . 2 . ; .  1 .  . ; 4 5 3 2; . . . .]. I want to obtain the vector [3 2 1 4 5 3 2]. I could not find any function that does this. Any idea is appreciated.

This seems like an odd thing to want.  What are you trying to do?