I'm interested in moving a vector to a single processor (so I can output it in some custom way), but I can't find a simple way to do that.

Is the easiest way to output the parallel vector to a file and then read it in to a single processor vector?

http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Vec/VecScatterCreateToZero.html

Also, an unrelated question: If I have a vector that I'm using as the result of a matrix vector product, but it is initially empty, do I need to initialize it in any way? or can I just create it and run with it:

… create x and A ...
VecCreate(world, &b);

This create is wrong, that Vec will be overwritten.

MatGetVecs(A,&x,&b);

You can jsut use these vectors.

Matt

… do stuff with x and A ...

MatMult(A,x,b);

Thanks for the help,

-Andrew