[petsc-users] Mixed 32-bit and 64-bit indices

[Daniel Langr]

Hi all,

is there any way to use 32-bit integers for indexing rows/columns and 
64-bit integers for indexing nonzeros at the same time in PETSc? I have 
a matrix with 4,559,168,066 nonzeros but only 448,797 rows/columns. For 
a general CSR scheme, the memory savings are almost 25% when using 
32-bit integers compared to 64-bit for indexing columns, which is really 
a lot of memory.

Thanks,
Daniel